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\input texinfo
@setfilename parallel_alternatives.info
@documentencoding utf-8
@settitle parallel_alternatives - Alternatives to GNU parallel
@node Top
@top parallel_alternatives
@menu
* NAME::
* DIFFERENCES BETWEEN GNU Parallel AND ALTERNATIVES::
* TESTING OTHER TOOLS::
* AUTHOR::
* LICENSE::
* DEPENDENCIES::
* SEE ALSO::
@end menu
@node NAME
@chapter NAME
parallel_alternatives - Alternatives to GNU @strong{parallel}
@node DIFFERENCES BETWEEN GNU Parallel AND ALTERNATIVES
@chapter DIFFERENCES BETWEEN GNU Parallel AND ALTERNATIVES
There are a lot programs with some of the functionality of GNU
@strong{parallel}. GNU @strong{parallel} strives to include the best of the
functionality without sacrificing ease of use.
@strong{parallel} has existed since 2002 and as GNU @strong{parallel} since
2010. A lot of the alternatives have not had the vitality to survive
that long, but have come and gone during that time.
GNU @strong{parallel} is actively maintained with a new release every month
since 2010. Most other alternatives are fleeting interests of the
developers with irregular releases and only maintained for a few
years.
@menu
* SUMMARY TABLE::
* DIFFERENCES BETWEEN xargs AND GNU Parallel::
* DIFFERENCES BETWEEN find -exec AND GNU Parallel::
* DIFFERENCES BETWEEN make -j AND GNU Parallel::
* DIFFERENCES BETWEEN ppss AND GNU Parallel::
* DIFFERENCES BETWEEN pexec AND GNU Parallel::
* DIFFERENCES BETWEEN xjobs AND GNU Parallel::
* DIFFERENCES BETWEEN prll AND GNU Parallel::
* DIFFERENCES BETWEEN dxargs AND GNU Parallel::
* DIFFERENCES BETWEEN mdm/middleman AND GNU Parallel::
* DIFFERENCES BETWEEN xapply AND GNU Parallel::
* DIFFERENCES BETWEEN AIX apply AND GNU Parallel::
* DIFFERENCES BETWEEN paexec AND GNU Parallel::
* DIFFERENCES BETWEEN map(sitaramc) AND GNU Parallel::
* DIFFERENCES BETWEEN ladon AND GNU Parallel::
* DIFFERENCES BETWEEN jobflow AND GNU Parallel::
* DIFFERENCES BETWEEN gargs AND GNU Parallel::
* DIFFERENCES BETWEEN orgalorg AND GNU Parallel::
* DIFFERENCES BETWEEN Rust parallel AND GNU Parallel::
* DIFFERENCES BETWEEN Rush AND GNU Parallel::
* DIFFERENCES BETWEEN ClusterSSH AND GNU Parallel::
* DIFFERENCES BETWEEN coshell AND GNU Parallel::
* DIFFERENCES BETWEEN spread AND GNU Parallel::
* DIFFERENCES BETWEEN pyargs AND GNU Parallel::
* DIFFERENCES BETWEEN concurrently AND GNU Parallel::
* DIFFERENCES BETWEEN map(soveran) AND GNU Parallel::
* DIFFERENCES BETWEEN loop AND GNU Parallel::
* DIFFERENCES BETWEEN lorikeet AND GNU Parallel::
* DIFFERENCES BETWEEN spp AND GNU Parallel::
* DIFFERENCES BETWEEN paral AND GNU Parallel::
* DIFFERENCES BETWEEN concurr AND GNU Parallel::
* DIFFERENCES BETWEEN lesser-parallel AND GNU Parallel::
* DIFFERENCES BETWEEN npm-parallel AND GNU Parallel::
* DIFFERENCES BETWEEN machma AND GNU Parallel::
* DIFFERENCES BETWEEN interlace AND GNU Parallel::
* DIFFERENCES BETWEEN otonvm Parallel AND GNU Parallel::
* DIFFERENCES BETWEEN k-bx par AND GNU Parallel::
* DIFFERENCES BETWEEN parallelshell AND GNU Parallel::
* DIFFERENCES BETWEEN shell-executor AND GNU Parallel::
* DIFFERENCES BETWEEN non-GNU par AND GNU Parallel::
* DIFFERENCES BETWEEN fd AND GNU Parallel::
* DIFFERENCES BETWEEN lateral AND GNU Parallel::
* DIFFERENCES BETWEEN with-this AND GNU Parallel::
* Todo::
@end menu
@node SUMMARY TABLE
@section SUMMARY TABLE
The following features are in some of the comparable tools:
@strong{Inputs}
I1. Arguments can be read from stdin
I2. Arguments can be read from a file
I3. Arguments can be read from multiple files
I4. Arguments can be read from command line
I5. Arguments can be read from a table
I6. Arguments can be read from the same file using #! (shebang)
I7. Line oriented input as default (Quoting of special chars not needed)
@strong{Manipulation of input}
M1. Composed command
M2. Multiple arguments can fill up an execution line
M3. Arguments can be put anywhere in the execution line
M4. Multiple arguments can be put anywhere in the execution line
M5. Arguments can be replaced with context
M6. Input can be treated as the complete command line
@strong{Outputs}
O1. Grouping output so output from different jobs do not mix
O2. Send stderr (standard error) to stderr (standard error)
O3. Send stdout (standard output) to stdout (standard output)
O4. Order of output can be same as order of input
O5. Stdout only contains stdout (standard output) from the command
O6. Stderr only contains stderr (standard error) from the command
O7. Buffering on disk
O8. Cleanup of file if killed
O9. Test if disk runs full during run
@strong{Execution}
E1. Running jobs in parallel
E2. List running jobs
E3. Finish running jobs, but do not start new jobs
E4. Number of running jobs can depend on number of cpus
E5. Finish running jobs, but do not start new jobs after first failure
E6. Number of running jobs can be adjusted while running
@strong{Remote execution}
R1. Jobs can be run on remote computers
R2. Basefiles can be transferred
R3. Argument files can be transferred
R4. Result files can be transferred
R5. Cleanup of transferred files
R6. No config files needed
R7. Do not run more than SSHD's MaxStartups can handle
R8. Configurable SSH command
R9. Retry if connection breaks occasionally
@strong{Semaphore}
S1. Possibility to work as a mutex
S2. Possibility to work as a counting semaphore
@strong{Legend}
- = no
x = not applicable
ID = yes
As every new version of the programs are not tested the table may be
outdated. Please file a bug-report if you find errors (See REPORTING
BUGS).
parallel:
I1 I2 I3 I4 I5 I6 I7
M1 M2 M3 M4 M5 M6
O1 O2 O3 O4 O5 O6 O7 O8 O9
E1 E2 E3 E4 E5 E6
R1 R2 R3 R4 R5 R6 R7 R8 R9
S1 S2
xargs:
I1 I2 - - - - -
- M2 M3 - - -
- O2 O3 - O5 O6
E1 - - - - -
- - - - - x - - -
- -
find -exec:
- - - x - x -
- M2 M3 - - - -
- O2 O3 O4 O5 O6
- - - - - - -
- - - - - - - - -
x x
make -j:
- - - - - - -
- - - - - -
O1 O2 O3 - x O6
E1 - - - E5 -
- - - - - - - - -
- -
ppss:
I1 I2 - - - - I7
M1 - M3 - - M6
O1 - - x - -
E1 E2 ?E3 E4 - -
R1 R2 R3 R4 - - ?R7 ? ?
- -
pexec:
I1 I2 - I4 I5 - -
M1 - M3 - - M6
O1 O2 O3 - O5 O6
E1 - - E4 - E6
R1 - - - - R6 - - -
S1 -
xjobs, prll, dxargs, mdm/middelman, xapply, paexec, ladon, jobflow,
ClusterSSH: TODO - Please file a bug-report if you know what features
they support (See REPORTING BUGS).
@node DIFFERENCES BETWEEN xargs AND GNU Parallel
@section DIFFERENCES BETWEEN xargs AND GNU Parallel
@strong{xargs} offers some of the same possibilities as GNU @strong{parallel}.
@strong{xargs} deals badly with special characters (such as space, \, ' and
"). To see the problem try this:
@verbatim
touch important_file
touch 'not important_file'
ls not* | xargs rm
mkdir -p "My brother's 12\" records"
ls | xargs rmdir
touch 'c:\windows\system32\clfs.sys'
echo 'c:\windows\system32\clfs.sys' | xargs ls -l
@end verbatim
You can specify @strong{-0}, but many input generators are not
optimized for using @strong{NUL} as separator but are optimized for
@strong{newline} as separator. E.g @strong{head}, @strong{tail}, @strong{awk}, @strong{ls}, @strong{echo},
@strong{sed}, @strong{tar -v}, @strong{perl} (@strong{-0} and \0 instead of \n), @strong{locate}
(requires using @strong{-0}), @strong{find} (requires using @strong{-print0}), @strong{grep}
(requires user to use @strong{-z} or @strong{-Z}), @strong{sort} (requires using @strong{-z}).
GNU @strong{parallel}'s newline separation can be emulated with:
@strong{cat | xargs -d "\n" -n1 @emph{command}}
@strong{xargs} can run a given number of jobs in parallel, but has no
support for running number-of-cpu-cores jobs in parallel.
@strong{xargs} has no support for grouping the output, therefore output may
run together, e.g. the first half of a line is from one process and
the last half of the line is from another process. The example
@strong{Parallel grep} cannot be done reliably with @strong{xargs} because of
this. To see this in action try:
@verbatim
parallel perl -e '\$a=\"1\".\"{}\"x10000000\;print\ \$a,\"\\n\"' \
'>' {} ::: a b c d e f g h
# Serial = no mixing = the wanted result
# 'tr -s a-z' squeezes repeating letters into a single letter
echo a b c d e f g h | xargs -P1 -n1 grep 1 | tr -s a-z
# Compare to 8 jobs in parallel
parallel -kP8 -n1 grep 1 ::: a b c d e f g h | tr -s a-z
echo a b c d e f g h | xargs -P8 -n1 grep 1 | tr -s a-z
echo a b c d e f g h | xargs -P8 -n1 grep --line-buffered 1 | \
tr -s a-z
@end verbatim
Or try this:
@verbatim
slow_seq() {
echo Count to "$@"
seq "$@" |
perl -ne '$|=1; for(split//){ print; select($a,$a,$a,0.100);}'
}
export -f slow_seq
# Serial = no mixing = the wanted result
seq 8 | xargs -n1 -P1 -I {} bash -c 'slow_seq {}'
# Compare to 8 jobs in parallel
seq 8 | parallel -P8 slow_seq {}
seq 8 | xargs -n1 -P8 -I {} bash -c 'slow_seq {}'
@end verbatim
@strong{xargs} has no support for keeping the order of the output, therefore
if running jobs in parallel using @strong{xargs} the output of the second
job cannot be postponed till the first job is done.
@strong{xargs} has no support for running jobs on remote computers.
@strong{xargs} has no support for context replace, so you will have to create the
arguments.
If you use a replace string in @strong{xargs} (@strong{-I}) you can not force
@strong{xargs} to use more than one argument.
Quoting in @strong{xargs} works like @strong{-q} in GNU @strong{parallel}. This means
composed commands and redirection require using @strong{bash -c}.
@verbatim
ls | parallel "wc {} >{}.wc"
ls | parallel "echo {}; ls {}|wc"
@end verbatim
becomes (assuming you have 8 cores and that none of the filenames
contain space, " or ').
@verbatim
ls | xargs -d "\n" -P8 -I {} bash -c "wc {} >{}.wc"
ls | xargs -d "\n" -P8 -I {} bash -c "echo {}; ls {}|wc"
@end verbatim
https://www.gnu.org/software/findutils/
@node DIFFERENCES BETWEEN find -exec AND GNU Parallel
@section DIFFERENCES BETWEEN find -exec AND GNU Parallel
@strong{find -exec} offers some of the same possibilities as GNU @strong{parallel}.
@strong{find -exec} only works on files. Processing other input (such as
hosts or URLs) will require creating these inputs as files. @strong{find
-exec} has no support for running commands in parallel.
https://www.gnu.org/software/findutils/ (Last checked: 2019-01)
@node DIFFERENCES BETWEEN make -j AND GNU Parallel
@section DIFFERENCES BETWEEN make -j AND GNU Parallel
@strong{make -j} can run jobs in parallel, but requires a crafted Makefile
to do this. That results in extra quoting to get filenames containing
newlines to work correctly.
@strong{make -j} computes a dependency graph before running jobs. Jobs run
by GNU @strong{parallel} does not depend on each other.
(Very early versions of GNU @strong{parallel} were coincidentally implemented
using @strong{make -j}).
https://www.gnu.org/software/make/ (Last checked: 2019-01)
@node DIFFERENCES BETWEEN ppss AND GNU Parallel
@section DIFFERENCES BETWEEN ppss AND GNU Parallel
@strong{ppss} is also a tool for running jobs in parallel.
The output of @strong{ppss} is status information and thus not useful for
using as input for another command. The output from the jobs are put
into files.
The argument replace string ($ITEM) cannot be changed. Arguments must
be quoted - thus arguments containing special characters (space '"&!*)
may cause problems. More than one argument is not supported. Filenames
containing newlines are not processed correctly. When reading input
from a file null cannot be used as a terminator. @strong{ppss} needs to read
the whole input file before starting any jobs.
Output and status information is stored in ppss_dir and thus requires
cleanup when completed. If the dir is not removed before running
@strong{ppss} again it may cause nothing to happen as @strong{ppss} thinks the
task is already done. GNU @strong{parallel} will normally not need cleaning
up if running locally and will only need cleaning up if stopped
abnormally and running remote (@strong{--cleanup} may not complete if
stopped abnormally). The example @strong{Parallel grep} would require extra
postprocessing if written using @strong{ppss}.
For remote systems PPSS requires 3 steps: config, deploy, and
start. GNU @strong{parallel} only requires one step.
@menu
* EXAMPLES FROM ppss MANUAL::
@end menu
@node EXAMPLES FROM ppss MANUAL
@subsection EXAMPLES FROM ppss MANUAL
Here are the examples from @strong{ppss}'s manual page with the equivalent
using GNU @strong{parallel}:
@strong{1} ./ppss.sh standalone -d /path/to/files -c 'gzip '
@strong{1} find /path/to/files -type f | parallel gzip
@strong{2} ./ppss.sh standalone -d /path/to/files -c 'cp "$ITEM" /destination/dir '
@strong{2} find /path/to/files -type f | parallel cp @{@} /destination/dir
@strong{3} ./ppss.sh standalone -f list-of-urls.txt -c 'wget -q '
@strong{3} parallel -a list-of-urls.txt wget -q
@strong{4} ./ppss.sh standalone -f list-of-urls.txt -c 'wget -q "$ITEM"'
@strong{4} parallel -a list-of-urls.txt wget -q @{@}
@strong{5} ./ppss config -C config.cfg -c 'encode.sh ' -d /source/dir -m
192.168.1.100 -u ppss -k ppss-key.key -S ./encode.sh -n nodes.txt -o
/some/output/dir --upload --download ; ./ppss deploy -C config.cfg ;
./ppss start -C config
@strong{5} # parallel does not use configs. If you want a different username put it in nodes.txt: user@@hostname
@strong{5} find source/dir -type f | parallel --sshloginfile nodes.txt --trc @{.@}.mp3 lame -a @{@} -o @{.@}.mp3 --preset standard --quiet
@strong{6} ./ppss stop -C config.cfg
@strong{6} killall -TERM parallel
@strong{7} ./ppss pause -C config.cfg
@strong{7} Press: CTRL-Z or killall -SIGTSTP parallel
@strong{8} ./ppss continue -C config.cfg
@strong{8} Enter: fg or killall -SIGCONT parallel
@strong{9} ./ppss.sh status -C config.cfg
@strong{9} killall -SIGUSR2 parallel
https://github.com/louwrentius/PPSS
@node DIFFERENCES BETWEEN pexec AND GNU Parallel
@section DIFFERENCES BETWEEN pexec AND GNU Parallel
@strong{pexec} is also a tool for running jobs in parallel.
@menu
* EXAMPLES FROM pexec MANUAL::
@end menu
@node EXAMPLES FROM pexec MANUAL
@subsection EXAMPLES FROM pexec MANUAL
Here are the examples from @strong{pexec}'s info page with the equivalent
using GNU @strong{parallel}:
@strong{1} pexec -o sqrt-%s.dat -p "$(seq 10)" -e NUM -n 4 -c -- \
'echo "scale=10000;sqrt($NUM)" | bc'
@strong{1} seq 10 | parallel -j4 'echo "scale=10000;sqrt(@{@})" | bc > sqrt-@{@}.dat'
@strong{2} pexec -p "$(ls myfiles*.ext)" -i %s -o %s.sort -- sort
@strong{2} ls myfiles*.ext | parallel sort @{@} ">@{@}.sort"
@strong{3} pexec -f image.list -n auto -e B -u star.log -c -- \
'fistar $B.fits -f 100 -F id,x,y,flux -o $B.star'
@strong{3} parallel -a image.list \
'fistar @{@}.fits -f 100 -F id,x,y,flux -o @{@}.star' 2>star.log
@strong{4} pexec -r *.png -e IMG -c -o - -- \
'convert $IMG $@{IMG%.png@}.jpeg ; "echo $IMG: done"'
@strong{4} ls *.png | parallel 'convert @{@} @{.@}.jpeg; echo @{@}: done'
@strong{5} pexec -r *.png -i %s -o %s.jpg -c 'pngtopnm | pnmtojpeg'
@strong{5} ls *.png | parallel 'pngtopnm < @{@} | pnmtojpeg > @{@}.jpg'
@strong{6} for p in *.png ; do echo $@{p%.png@} ; done | \
pexec -f - -i %s.png -o %s.jpg -c 'pngtopnm | pnmtojpeg'
@strong{6} ls *.png | parallel 'pngtopnm < @{@} | pnmtojpeg > @{.@}.jpg'
@strong{7} LIST=$(for p in *.png ; do echo $@{p%.png@} ; done)
pexec -r $LIST -i %s.png -o %s.jpg -c 'pngtopnm | pnmtojpeg'
@strong{7} ls *.png | parallel 'pngtopnm < @{@} | pnmtojpeg > @{.@}.jpg'
@strong{8} pexec -n 8 -r *.jpg -y unix -e IMG -c \
'pexec -j -m blockread -d $IMG | \
jpegtopnm | pnmscale 0.5 | pnmtojpeg | \
pexec -j -m blockwrite -s th_$IMG'
@strong{8} Combining GNU @strong{parallel} and GNU @strong{sem}.
@strong{8} ls *jpg | parallel -j8 'sem --id blockread cat @{@} | jpegtopnm |' \
'pnmscale 0.5 | pnmtojpeg | sem --id blockwrite cat > th_@{@}'
@strong{8} If reading and writing is done to the same disk, this may be
faster as only one process will be either reading or writing:
@strong{8} ls *jpg | parallel -j8 'sem --id diskio cat @{@} | jpegtopnm |' \
'pnmscale 0.5 | pnmtojpeg | sem --id diskio cat > th_@{@}'
https://www.gnu.org/software/pexec/
@node DIFFERENCES BETWEEN xjobs AND GNU Parallel
@section DIFFERENCES BETWEEN xjobs AND GNU Parallel
@strong{xjobs} is also a tool for running jobs in parallel. It only supports
running jobs on your local computer.
@strong{xjobs} deals badly with special characters just like @strong{xargs}. See
the section @strong{DIFFERENCES BETWEEN xargs AND GNU Parallel}.
Here are the examples from @strong{xjobs}'s man page with the equivalent
using GNU @strong{parallel}:
@strong{1} ls -1 *.zip | xjobs unzip
@strong{1} ls *.zip | parallel unzip
@strong{2} ls -1 *.zip | xjobs -n unzip
@strong{2} ls *.zip | parallel unzip >/dev/null
@strong{3} find . -name '*.bak' | xjobs gzip
@strong{3} find . -name '*.bak' | parallel gzip
@strong{4} ls -1 *.jar | sed 's/\(.*\)/\1 > \1.idx/' | xjobs jar tf
@strong{4} ls *.jar | parallel jar tf @{@} '>' @{@}.idx
@strong{5} xjobs -s script
@strong{5} cat script | parallel
@strong{6} mkfifo /var/run/my_named_pipe;
xjobs -s /var/run/my_named_pipe &
echo unzip 1.zip >> /var/run/my_named_pipe;
echo tar cf /backup/myhome.tar /home/me >> /var/run/my_named_pipe
@strong{6} mkfifo /var/run/my_named_pipe;
cat /var/run/my_named_pipe | parallel &
echo unzip 1.zip >> /var/run/my_named_pipe;
echo tar cf /backup/myhome.tar /home/me >> /var/run/my_named_pipe
http://www.maier-komor.de/xjobs.html (Last checked: 2019-01)
@node DIFFERENCES BETWEEN prll AND GNU Parallel
@section DIFFERENCES BETWEEN prll AND GNU Parallel
@strong{prll} is also a tool for running jobs in parallel. It does not
support running jobs on remote computers.
@strong{prll} encourages using BASH aliases and BASH functions instead of
scripts. GNU @strong{parallel} supports scripts directly, functions if they
are exported using @strong{export -f}, and aliases if using @strong{env_parallel}.
@strong{prll} generates a lot of status information on stderr (standard
error) which makes it harder to use the stderr (standard error) output
of the job directly as input for another program.
Here is the example from @strong{prll}'s man page with the equivalent
using GNU @strong{parallel}:
@verbatim
prll -s 'mogrify -flip $1' *.jpg
parallel mogrify -flip ::: *.jpg
@end verbatim
https://github.com/exzombie/prll (Last checked: 2019-01)
@node DIFFERENCES BETWEEN dxargs AND GNU Parallel
@section DIFFERENCES BETWEEN dxargs AND GNU Parallel
@strong{dxargs} is also a tool for running jobs in parallel.
@strong{dxargs} does not deal well with more simultaneous jobs than SSHD's
MaxStartups. @strong{dxargs} is only built for remote run jobs, but does not
support transferring of files.
https://web.archive.org/web/20120518070250/http://www.semicomplete.com/blog/geekery/distributed-xargs.html (Last checked: 2019-01)
@node DIFFERENCES BETWEEN mdm/middleman AND GNU Parallel
@section DIFFERENCES BETWEEN mdm/middleman AND GNU Parallel
middleman(mdm) is also a tool for running jobs in parallel.
Here are the shellscripts of
https://web.archive.org/web/20110728064735/http://mdm.berlios.de/usage.html
ported to GNU @strong{parallel}:
@verbatim
seq 19 | parallel buffon -o - | sort -n > result
cat files | parallel cmd
find dir -execdir sem cmd {} \;
@end verbatim
https://github.com/cklin/mdm (Last checked: 2019-01)
@node DIFFERENCES BETWEEN xapply AND GNU Parallel
@section DIFFERENCES BETWEEN xapply AND GNU Parallel
@strong{xapply} can run jobs in parallel on the local computer.
Here are the examples from @strong{xapply}'s man page with the equivalent
using GNU @strong{parallel}:
@strong{1} xapply '(cd %1 && make all)' */
@strong{1} parallel 'cd @{@} && make all' ::: */
@strong{2} xapply -f 'diff %1 ../version5/%1' manifest | more
@strong{2} parallel diff @{@} ../version5/@{@} < manifest | more
@strong{3} xapply -p/dev/null -f 'diff %1 %2' manifest1 checklist1
@strong{3} parallel --link diff @{1@} @{2@} :::: manifest1 checklist1
@strong{4} xapply 'indent' *.c
@strong{4} parallel indent ::: *.c
@strong{5} find ~ksb/bin -type f ! -perm -111 -print | xapply -f -v 'chmod a+x' -
@strong{5} find ~ksb/bin -type f ! -perm -111 -print | parallel -v chmod a+x
@strong{6} find */ -... | fmt 960 1024 | xapply -f -i /dev/tty 'vi' -
@strong{6} sh <(find */ -... | parallel -s 1024 echo vi)
@strong{6} find */ -... | parallel -s 1024 -Xuj1 vi
@strong{7} find ... | xapply -f -5 -i /dev/tty 'vi' - - - - -
@strong{7} sh <(find ... |parallel -n5 echo vi)
@strong{7} find ... |parallel -n5 -uj1 vi
@strong{8} xapply -fn "" /etc/passwd
@strong{8} parallel -k echo < /etc/passwd
@strong{9} tr ':' '\012' < /etc/passwd | xapply -7 -nf 'chown %1 %6' - - - - - - -
@strong{9} tr ':' '\012' < /etc/passwd | parallel -N7 chown @{1@} @{6@}
@strong{10} xapply '[ -d %1/RCS ] || echo %1' */
@strong{10} parallel '[ -d @{@}/RCS ] || echo @{@}' ::: */
@strong{11} xapply -f '[ -f %1 ] && echo %1' List | ...
@strong{11} parallel '[ -f @{@} ] && echo @{@}' < List | ...
https://web.archive.org/web/20160702211113/
http://carrera.databits.net/~ksb/msrc/local/bin/xapply/xapply.html
@node DIFFERENCES BETWEEN AIX apply AND GNU Parallel
@section DIFFERENCES BETWEEN AIX apply AND GNU Parallel
@strong{apply} can build command lines based on a template and arguments -
very much like GNU @strong{parallel}. @strong{apply} does not run jobs in
parallel. @strong{apply} does not use an argument separator (like @strong{:::});
instead the template must be the first argument.
Here are the examples from IBM's Knowledge Center and the
corresponding command using GNU @strong{parallel}:
1. To obtain results similar to those of the @strong{ls} command, enter:
@verbatim
apply echo *
parallel echo ::: *
@end verbatim
2. To compare the file named @strong{a1} to the file named @strong{b1}, and the
file named @strong{a2} to the file named @strong{b2}, enter:
@verbatim
apply -2 cmp a1 b1 a2 b2
parallel -N2 cmp ::: a1 b1 a2 b2
@end verbatim
3. To run the @strong{who} command five times, enter:
@verbatim
apply -0 who 1 2 3 4 5
parallel -N0 who ::: 1 2 3 4 5
@end verbatim
4. To link all files in the current directory to the directory
@strong{/usr/joe}, enter:
@verbatim
apply 'ln %1 /usr/joe' *
parallel ln {} /usr/joe ::: *
@end verbatim
https://www-01.ibm.com/support/knowledgecenter/ssw_aix_71/com.ibm.aix.cmds1/apply.htm (Last checked: 2019-01)
@node DIFFERENCES BETWEEN paexec AND GNU Parallel
@section DIFFERENCES BETWEEN paexec AND GNU Parallel
@strong{paexec} can run jobs in parallel on both the local and remote computers.
@strong{paexec} requires commands to print a blank line as the last
output. This means you will have to write a wrapper for most programs.
@strong{paexec} has a job dependency facility so a job can depend on another
job to be executed successfully. Sort of a poor-man's @strong{make}.
Here are the examples from @strong{paexec}'s example catalog with the equivalent
using GNU @strong{parallel}:
@table @asis
@item 1_div_X_run:
@anchor{1_div_X_run:}
@verbatim
../../paexec -s -l -c "`pwd`/1_div_X_cmd" -n +1 <<EOF [...]
parallel echo {} '|' `pwd`/1_div_X_cmd <<EOF [...]
@end verbatim
@item all_substr_run:
@anchor{all_substr_run:}
@verbatim
../../paexec -lp -c "`pwd`/all_substr_cmd" -n +3 <<EOF [...]
parallel echo {} '|' `pwd`/all_substr_cmd <<EOF [...]
@end verbatim
@item cc_wrapper_run:
@anchor{cc_wrapper_run:}
@verbatim
../../paexec -c "env CC=gcc CFLAGS=-O2 `pwd`/cc_wrapper_cmd" \
-n 'host1 host2' \
-t '/usr/bin/ssh -x' <<EOF [...]
parallel echo {} '|' "env CC=gcc CFLAGS=-O2 `pwd`/cc_wrapper_cmd" \
-S host1,host2 <<EOF [...]
# This is not exactly the same, but avoids the wrapper
parallel gcc -O2 -c -o {.}.o {} \
-S host1,host2 <<EOF [...]
@end verbatim
@item toupper_run:
@anchor{toupper_run:}
@verbatim
../../paexec -lp -c "`pwd`/toupper_cmd" -n +10 <<EOF [...]
parallel echo {} '|' ./toupper_cmd <<EOF [...]
# Without the wrapper:
parallel echo {} '| awk {print\ toupper\(\$0\)}' <<EOF [...]
@end verbatim
@end table
https://github.com/cheusov/paexec
@node DIFFERENCES BETWEEN map(sitaramc) AND GNU Parallel
@section DIFFERENCES BETWEEN map(sitaramc) AND GNU Parallel
@strong{map} sees it as a feature to have less features and in doing so it
also handles corner cases incorrectly. A lot of GNU @strong{parallel}'s code
is to handle corner cases correctly on every platform, so you will not
get a nasty surprise if a user, for example, saves a file called: @emph{My
brother's 12" records.txt}
@strong{map}'s example showing how to deal with special characters fails on
special characters:
@verbatim
echo "The Cure" > My\ brother\'s\ 12\"\ records
ls | \
map 'echo -n `gzip < "%" | wc -c`; echo -n '*100/'; wc -c < "%"' |
bc
@end verbatim
It works with GNU @strong{parallel}:
@verbatim
ls | \
parallel \
'echo -n `gzip < {} | wc -c`; echo -n '*100/'; wc -c < {}' | bc
@end verbatim
And you can even get the file name prepended:
@verbatim
ls | \
parallel --tag \
'(echo -n `gzip < {} | wc -c`'*100/'; wc -c < {}) | bc'
@end verbatim
@strong{map} has no support for grouping. So this gives the wrong results
without any warnings:
@verbatim
parallel perl -e '\$a=\"1{}\"x10000000\;print\ \$a,\"\\n\"' '>' {} \
::: a b c d e f
ls -l a b c d e f
parallel -kP4 -n1 grep 1 > out.par ::: a b c d e f
map -p 4 'grep 1' a b c d e f > out.map-unbuf
map -p 4 'grep --line-buffered 1' a b c d e f > out.map-linebuf
map -p 1 'grep --line-buffered 1' a b c d e f > out.map-serial
ls -l out*
md5sum out*
@end verbatim
The documentation shows a workaround, but not only does that mix
stdout (standard output) with stderr (standard error) it also fails
completely for certain jobs (and may even be considered less readable):
@verbatim
parallel echo -n {} ::: 1 2 3
map -p 4 'echo -n % 2>&1 | sed -e "s/^/$$:/"' 1 2 3 | \
sort | cut -f2- -d:
@end verbatim
@strong{map}s replacement strings (% %D %B %E) can be simulated in GNU
@strong{parallel} by putting this in @strong{~/.parallel/config}:
@verbatim
--rpl '%'
--rpl '%D $_=Q(::dirname($_));'
--rpl '%B s:.*/::;s:\.[^/.]+$::;'
--rpl '%E s:.*\.::'
@end verbatim
@strong{map} does not have an argument separator on the command line, but
uses the first argument as command. This makes quoting harder which again
may affect readability. Compare:
@verbatim
map -p 2 'perl -ne '"'"'/^\S+\s+\S+$/ and print $ARGV,"\n"'"'" *
parallel -q perl -ne '/^\S+\s+\S+$/ and print $ARGV,"\n"' ::: *
@end verbatim
@strong{map} can do multiple arguments with context replace, but not without
context replace:
@verbatim
parallel --xargs echo 'BEGIN{'{}'}END' ::: 1 2 3
map "echo 'BEGIN{'%'}END'" 1 2 3
@end verbatim
@strong{map} requires Perl v5.10.0 making it harder to use on old systems.
@strong{map} has no way of using % in the command (GNU @strong{parallel} has -I to
specify another replacement string than @strong{@{@}}).
By design @strong{map} is option incompatible with @strong{xargs}, it does not
have remote job execution, a structured way of saving results,
multiple input sources, progress indicator, configurable record
delimiter (only field delimiter), logging of jobs run with possibility
to resume, keeping the output in the same order as input, --pipe
processing, and dynamically timeouts.
https://github.com/sitaramc/map
@node DIFFERENCES BETWEEN ladon AND GNU Parallel
@section DIFFERENCES BETWEEN ladon AND GNU Parallel
@strong{ladon} can run multiple jobs on files in parallel.
@strong{ladon} only works on files and the only way to specify files is
using a quoted glob string (such as \*.jpg). It is not possible to
list the files manually.
As replacement strings it uses FULLPATH DIRNAME BASENAME EXT RELDIR
RELPATH
These can be simulated using GNU @strong{parallel} by putting this in
@strong{~/.parallel/config}:
@verbatim
--rpl 'FULLPATH $_=Q($_);chomp($_=qx{readlink -f $_});'
--rpl 'DIRNAME $_=Q(::dirname($_));chomp($_=qx{readlink -f $_});'
--rpl 'BASENAME s:.*/::;s:\.[^/.]+$::;'
--rpl 'EXT s:.*\.::'
--rpl 'RELDIR $_=Q($_);chomp(($_,$c)=qx{readlink -f $_;pwd});
s:\Q$c/\E::;$_=::dirname($_);'
--rpl 'RELPATH $_=Q($_);chomp(($_,$c)=qx{readlink -f $_;pwd});
s:\Q$c/\E::;'
@end verbatim
@strong{ladon} deals badly with filenames containing " and newline, and it
fails for output larger than 200k:
@verbatim
ladon '*' -- seq 36000 | wc
@end verbatim
@menu
* EXAMPLES FROM ladon MANUAL::
@end menu
@node EXAMPLES FROM ladon MANUAL
@subsection EXAMPLES FROM ladon MANUAL
It is assumed that the '--rpl's above are put in @strong{~/.parallel/config}
and that it is run under a shell that supports '**' globbing (such as @strong{zsh}):
@strong{1} ladon "**/*.txt" -- echo RELPATH
@strong{1} parallel echo RELPATH ::: **/*.txt
@strong{2} ladon "~/Documents/**/*.pdf" -- shasum FULLPATH >hashes.txt
@strong{2} parallel shasum FULLPATH ::: ~/Documents/**/*.pdf >hashes.txt
@strong{3} ladon -m thumbs/RELDIR "**/*.jpg" -- convert FULLPATH -thumbnail 100x100^ -gravity center -extent 100x100 thumbs/RELPATH
@strong{3} parallel mkdir -p thumbs/RELDIR\; convert FULLPATH -thumbnail 100x100^ -gravity center -extent 100x100 thumbs/RELPATH ::: **/*.jpg
@strong{4} ladon "~/Music/*.wav" -- lame -V 2 FULLPATH DIRNAME/BASENAME.mp3
@strong{4} parallel lame -V 2 FULLPATH DIRNAME/BASENAME.mp3 ::: ~/Music/*.wav
https://github.com/danielgtaylor/ladon (Last checked: 2019-01)
@node DIFFERENCES BETWEEN jobflow AND GNU Parallel
@section DIFFERENCES BETWEEN jobflow AND GNU Parallel
@strong{jobflow} can run multiple jobs in parallel.
Just like @strong{xargs} output from @strong{jobflow} jobs running in parallel mix
together by default. @strong{jobflow} can buffer into files (placed in
/run/shm), but these are not cleaned up if @strong{jobflow} dies
unexpectedly (e.g. by Ctrl-C). If the total output is big (in the
order of RAM+swap) it can cause the system to slow to a crawl and
eventually run out of memory.
@strong{jobflow} gives no error if the command is unknown, and like @strong{xargs}
redirection and composed commands require wrapping with @strong{bash -c}.
Input lines can at most be 4096 bytes. You can at most have 16 @{@}'s in
the command template. More than that either crashes the program or
simple does not execute the command.
@strong{jobflow} has no equivalent for @strong{--pipe}, or @strong{--sshlogin}.
@strong{jobflow} makes it possible to set resource limits on the running
jobs. This can be emulated by GNU @strong{parallel} using @strong{bash}'s @strong{ulimit}:
@verbatim
jobflow -limits=mem=100M,cpu=3,fsize=20M,nofiles=300 myjob
parallel 'ulimit -v 102400 -t 3 -f 204800 -n 300 myjob'
@end verbatim
@menu
* EXAMPLES FROM jobflow README::
@end menu
@node EXAMPLES FROM jobflow README
@subsection EXAMPLES FROM jobflow README
@strong{1} cat things.list | jobflow -threads=8 -exec ./mytask @{@}
@strong{1} cat things.list | parallel -j8 ./mytask @{@}
@strong{2} seq 100 | jobflow -threads=100 -exec echo @{@}
@strong{2} seq 100 | parallel -j100 echo @{@}
@strong{3} cat urls.txt | jobflow -threads=32 -exec wget @{@}
@strong{3} cat urls.txt | parallel -j32 wget @{@}
@strong{4} find . -name '*.bmp' | jobflow -threads=8 -exec bmp2jpeg @{.@}.bmp @{.@}.jpg
@strong{4} find . -name '*.bmp' | parallel -j8 bmp2jpeg @{.@}.bmp @{.@}.jpg
https://github.com/rofl0r/jobflow
@node DIFFERENCES BETWEEN gargs AND GNU Parallel
@section DIFFERENCES BETWEEN gargs AND GNU Parallel
@strong{gargs} can run multiple jobs in parallel.
Older versions cache output in memory. This causes it to be extremely
slow when the output is larger than the physical RAM, and can cause
the system to run out of memory.
See more details on this in @strong{man parallel_design}.
Newer versions cache output in files, but leave files in $TMPDIR if it
is killed.
Output to stderr (standard error) is changed if the command fails.
Here are the two examples from @strong{gargs} website.
@strong{1} seq 12 -1 1 | gargs -p 4 -n 3 "sleep @{0@}; echo @{1@} @{2@}"
@strong{1} seq 12 -1 1 | parallel -P 4 -n 3 "sleep @{1@}; echo @{2@} @{3@}"
@strong{2} cat t.txt | gargs --sep "\s+" -p 2 "echo '@{0@}:@{1@}-@{2@}' full-line: \'@{@}\'"
@strong{2} cat t.txt | parallel --colsep "\\s+" -P 2 "echo '@{1@}:@{2@}-@{3@}' full-line: \'@{@}\'"
https://github.com/brentp/gargs
@node DIFFERENCES BETWEEN orgalorg AND GNU Parallel
@section DIFFERENCES BETWEEN orgalorg AND GNU Parallel
@strong{orgalorg} can run the same job on multiple machines. This is related
to @strong{--onall} and @strong{--nonall}.
@strong{orgalorg} supports entering the SSH password - provided it is the
same for all servers. GNU @strong{parallel} advocates using @strong{ssh-agent}
instead, but it is possible to emulate @strong{orgalorg}'s behavior by
setting SSHPASS and by using @strong{--ssh "sshpass ssh"}.
To make the emulation easier, make a simple alias:
@verbatim
alias par_emul="parallel -j0 --ssh 'sshpass ssh' --nonall --tag --lb"
@end verbatim
If you want to supply a password run:
@verbatim
SSHPASS=`ssh-askpass`
@end verbatim
or set the password directly:
@verbatim
SSHPASS=P4$$w0rd!
@end verbatim
If the above is set up you can then do:
@verbatim
orgalorg -o frontend1 -o frontend2 -p -C uptime
par_emul -S frontend1 -S frontend2 uptime
orgalorg -o frontend1 -o frontend2 -p -C top -bid 1
par_emul -S frontend1 -S frontend2 top -bid 1
orgalorg -o frontend1 -o frontend2 -p -er /tmp -n \
'md5sum /tmp/bigfile' -S bigfile
par_emul -S frontend1 -S frontend2 --basefile bigfile --workdir /tmp \
md5sum /tmp/bigfile
@end verbatim
@strong{orgalorg} has a progress indicator for the transferring of a
file. GNU @strong{parallel} does not.
https://github.com/reconquest/orgalorg
@node DIFFERENCES BETWEEN Rust parallel AND GNU Parallel
@section DIFFERENCES BETWEEN Rust parallel AND GNU Parallel
Rust parallel focuses on speed. It is almost as fast as @strong{xargs}. It
implements a few features from GNU @strong{parallel}, but lacks many
functions. All these fail:
@verbatim
# Read arguments from file
parallel -a file echo
# Changing the delimiter
parallel -d _ echo ::: a_b_c_
@end verbatim
These do something different from GNU @strong{parallel}
@verbatim
# -q to protect quoted $ and space
parallel -q perl -e '$a=shift; print "$a"x10000000' ::: a b c
# Generation of combination of inputs
parallel echo {1} {2} ::: red green blue ::: S M L XL XXL
# {= perl expression =} replacement string
parallel echo '{= s/new/old/ =}' ::: my.new your.new
# --pipe
seq 100000 | parallel --pipe wc
# linked arguments
parallel echo ::: S M L :::+ sml med lrg ::: R G B :::+ red grn blu
# Run different shell dialects
zsh -c 'parallel echo \={} ::: zsh && true'
csh -c 'parallel echo \$\{\} ::: shell && true'
bash -c 'parallel echo \$\({}\) ::: pwd && true'
# Rust parallel does not start before the last argument is read
(seq 10; sleep 5; echo 2) | time parallel -j2 'sleep 2; echo'
tail -f /var/log/syslog | parallel echo
@end verbatim
Most of the examples from the book GNU Parallel 2018 do not work, thus
Rust parallel is not close to being a compatible replacement.
Rust parallel has no remote facilities.
It uses /tmp/parallel for tmp files and does not clean up if
terminated abruptly. If another user on the system uses Rust parallel,
then /tmp/parallel will have the wrong permissions and Rust parallel
will fail. A malicious user can setup the right permissions and
symlink the output file to one of the user's files and next time the
user uses Rust parallel it will overwrite this file.
@verbatim
attacker$ mkdir /tmp/parallel
attacker$ chmod a+rwX /tmp/parallel
# Symlink to the file the attacker wants to zero out
attacker$ ln -s ~victim/.important-file /tmp/parallel/stderr_1
victim$ seq 1000 | parallel echo
# This file is now overwritten with stderr from 'echo'
victim$ cat ~victim/.important-file
@end verbatim
If /tmp/parallel runs full during the run, Rust parallel does not
report this, but finishes with success - thereby risking data loss.
https://github.com/mmstick/parallel
@node DIFFERENCES BETWEEN Rush AND GNU Parallel
@section DIFFERENCES BETWEEN Rush AND GNU Parallel
@strong{rush} (https://github.com/shenwei356/rush) is written in Go and
based on @strong{gargs}.
Just like GNU @strong{parallel} @strong{rush} buffers in temporary files. But
opposite GNU @strong{parallel} @strong{rush} does not clean up, if the process
dies abnormally.
@strong{rush} has some string manipulations that can be emulated by putting
this into ~/.parallel/config (/ is used instead of %, and % is used
instead of ^ as that is closer to bash's $@{var%postfix@}):
@verbatim
--rpl '{:} s:(\.[^/]+)*$::'
--rpl '{:%([^}]+?)} s:$$1(\.[^/]+)*$::'
--rpl '{/:%([^}]*?)} s:.*/(.*)$$1(\.[^/]+)*$:$1:'
--rpl '{/:} s:(.*/)?([^/.]+)(\.[^/]+)*$:$2:'
--rpl '{@(.*?)} /$$1/ and $_=$1;'
@end verbatim
Here are the examples from @strong{rush}'s website with the equivalent
command in GNU @strong{parallel}.
@menu
* EXAMPLES::
* Other @strong{rush} features::
@end menu
@node EXAMPLES
@subsection EXAMPLES
@strong{1. Simple run, quoting is not necessary}
@verbatim
$ seq 1 3 | rush echo {}
$ seq 1 3 | parallel echo {}
@end verbatim
@strong{2. Read data from file (`-i`)}
@verbatim
$ rush echo {} -i data1.txt -i data2.txt
$ cat data1.txt data2.txt | parallel echo {}
@end verbatim
@strong{3. Keep output order (`-k`)}
@verbatim
$ seq 1 3 | rush 'echo {}' -k
$ seq 1 3 | parallel -k echo {}
@end verbatim
@strong{4. Timeout (`-t`)}
@verbatim
$ time seq 1 | rush 'sleep 2; echo {}' -t 1
$ time seq 1 | parallel --timeout 1 'sleep 2; echo {}'
@end verbatim
@strong{5. Retry (`-r`)}
@verbatim
$ seq 1 | rush 'python unexisted_script.py' -r 1
$ seq 1 | parallel --retries 2 'python unexisted_script.py'
@end verbatim
Use @strong{-u} to see it is really run twice:
@verbatim
$ seq 1 | parallel -u --retries 2 'python unexisted_script.py'
@end verbatim
@strong{6. Dirname (`@{/@}`) and basename (`@{%@}`) and remove custom
suffix (`@{^suffix@}`)}
@verbatim
$ echo dir/file_1.txt.gz | rush 'echo {/} {%} {^_1.txt.gz}'
$ echo dir/file_1.txt.gz |
parallel --plus echo {//} {/} {%_1.txt.gz}
@end verbatim
@strong{7. Get basename, and remove last (`@{.@}`) or any (`@{:@}`) extension}
@verbatim
$ echo dir.d/file.txt.gz | rush 'echo {.} {:} {%.} {%:}'
$ echo dir.d/file.txt.gz | parallel 'echo {.} {:} {/.} {/:}'
@end verbatim
@strong{8. Job ID, combine fields index and other replacement strings}
@verbatim
$ echo 12 file.txt dir/s_1.fq.gz |
rush 'echo job {#}: {2} {2.} {3%:^_1}'
$ echo 12 file.txt dir/s_1.fq.gz |
parallel --colsep ' ' 'echo job {#}: {2} {2.} {3/:%_1}'
@end verbatim
@strong{9. Capture submatch using regular expression (`@{@@regexp@}`)}
@verbatim
$ echo read_1.fq.gz | rush 'echo {@(.+)_\d}'
$ echo read_1.fq.gz | parallel 'echo {@(.+)_\d}'
@end verbatim
@strong{10. Custom field delimiter (`-d`)}
@verbatim
$ echo a=b=c | rush 'echo {1} {2} {3}' -d =
$ echo a=b=c | parallel -d = echo {1} {2} {3}
@end verbatim
@strong{11. Send multi-lines to every command (`-n`)}
@verbatim
$ seq 5 | rush -n 2 -k 'echo "{}"; echo'
$ seq 5 |
parallel -n 2 -k \
'echo {=-1 $_=join"\n",@arg[1..$#arg] =}; echo'
$ seq 5 | rush -n 2 -k 'echo "{}"; echo' -J ' '
$ seq 5 | parallel -n 2 -k 'echo {}; echo'
@end verbatim
@strong{12. Custom record delimiter (`-D`), note that empty records are not used.}
@verbatim
$ echo a b c d | rush -D " " -k 'echo {}'
$ echo a b c d | parallel -d " " -k 'echo {}'
$ echo abcd | rush -D "" -k 'echo {}'
Cannot be done by GNU Parallel
$ cat fasta.fa
>seq1
tag
>seq2
cat
gat
>seq3
attac
a
cat
$ cat fasta.fa | rush -D ">" \
'echo FASTA record {#}: name: {1} sequence: {2}' -k -d "\n"
# rush fails to join the multiline sequences
$ cat fasta.fa | (read -n1 ignore_first_char;
parallel -d '>' --colsep '\n' echo FASTA record {#}: \
name: {1} sequence: '{=2 $_=join"",@arg[2..$#arg]=}'
)
@end verbatim
@strong{13. Assign value to variable, like `awk -v` (`-v`)}
@verbatim
$ seq 1 |
rush 'echo Hello, {fname} {lname}!' -v fname=Wei -v lname=Shen
$ seq 1 |
parallel -N0 \
'fname=Wei; lname=Shen; echo Hello, ${fname} ${lname}!'
$ for var in a b; do \
$ seq 1 3 | rush -k -v var=$var 'echo var: {var}, data: {}'; \
$ done
@end verbatim
In GNU @strong{parallel} you would typically do:
@verbatim
$ seq 1 3 | parallel -k echo var: {1}, data: {2} ::: a b :::: -
@end verbatim
If you @emph{really} want the var:
@verbatim
$ seq 1 3 |
parallel -k var={1} ';echo var: $var, data: {}' ::: a b :::: -
@end verbatim
If you @emph{really} want the @strong{for}-loop:
@verbatim
$ for var in a b; do
> export var;
> seq 1 3 | parallel -k 'echo var: $var, data: {}';
> done
@end verbatim
Contrary to @strong{rush} this also works if the value is complex like:
@verbatim
My brother's 12" records
@end verbatim
@strong{14. @strong{Preset variable} (`-v`), avoid repeatedly writing verbose replacement strings}
@verbatim
# naive way
$ echo read_1.fq.gz | rush 'echo {:^_1} {:^_1}_2.fq.gz'
$ echo read_1.fq.gz | parallel 'echo {:%_1} {:%_1}_2.fq.gz'
# macro + removing suffix
$ echo read_1.fq.gz |
rush -v p='{:^_1}' 'echo {p} {p}_2.fq.gz'
$ echo read_1.fq.gz |
parallel 'p={:%_1}; echo $p ${p}_2.fq.gz'
# macro + regular expression
$ echo read_1.fq.gz | rush -v p='{@(.+?)_\d}' 'echo {p} {p}_2.fq.gz'
$ echo read_1.fq.gz | parallel 'p={@(.+?)_\d}; echo $p ${p}_2.fq.gz'
@end verbatim
Contrary to @strong{rush} GNU @strong{parallel} works with complex values:
@verbatim
echo "My brother's 12\"read_1.fq.gz" |
parallel 'p={@(.+?)_\d}; echo $p ${p}_2.fq.gz'
@end verbatim
@strong{15. Interrupt jobs by `Ctrl-C`, rush will stop unfinished commands and exit.}
@verbatim
$ seq 1 20 | rush 'sleep 1; echo {}'
^C
$ seq 1 20 | parallel 'sleep 1; echo {}'
^C
@end verbatim
@strong{16. Continue/resume jobs (`-c`). When some jobs failed (by
execution failure, timeout, or canceling by user with `Ctrl + C`),
please switch flag `-c/--continue` on and run again, so that `rush`
can save successful commands and ignore them in @emph{NEXT} run.}
@verbatim
$ seq 1 3 | rush 'sleep {}; echo {}' -t 3 -c
$ cat successful_cmds.rush
$ seq 1 3 | rush 'sleep {}; echo {}' -t 3 -c
$ seq 1 3 | parallel --joblog mylog --timeout 2 \
'sleep {}; echo {}'
$ cat mylog
$ seq 1 3 | parallel --joblog mylog --retry-failed \
'sleep {}; echo {}'
@end verbatim
Multi-line jobs:
@verbatim
$ seq 1 3 | rush 'sleep {}; echo {}; \
echo finish {}' -t 3 -c -C finished.rush
$ cat finished.rush
$ seq 1 3 | rush 'sleep {}; echo {}; \
echo finish {}' -t 3 -c -C finished.rush
$ seq 1 3 |
parallel --joblog mylog --timeout 2 'sleep {}; echo {}; \
echo finish {}'
$ cat mylog
$ seq 1 3 |
parallel --joblog mylog --retry-failed 'sleep {}; echo {}; \
echo finish {}'
@end verbatim
@strong{17. A comprehensive example: downloading 1K+ pages given by
three URL list files using `phantomjs save_page.js` (some page
contents are dynamically generated by Javascript, so `wget` does not
work). Here I set max jobs number (`-j`) as `20`, each job has a max
running time (`-t`) of `60` seconds and `3` retry changes
(`-r`). Continue flag `-c` is also switched on, so we can continue
unfinished jobs. Luckily, it's accomplished in one run :)}
@verbatim
$ for f in $(seq 2014 2016); do \
$ /bin/rm -rf $f; mkdir -p $f; \
$ cat $f.html.txt | rush -v d=$f -d = \
'phantomjs save_page.js "{}" > {d}/{3}.html' \
-j 20 -t 60 -r 3 -c; \
$ done
@end verbatim
GNU @strong{parallel} can append to an existing joblog with '+':
@verbatim
$ rm mylog
$ for f in $(seq 2014 2016); do
/bin/rm -rf $f; mkdir -p $f;
cat $f.html.txt |
parallel -j20 --timeout 60 --retries 4 --joblog +mylog \
--colsep = \
phantomjs save_page.js {1}={2}={3} '>' $f/{3}.html
done
@end verbatim
@strong{18. A bioinformatics example: mapping with `bwa`, and
processing result with `samtools`:}
@verbatim
$ ref=ref/xxx.fa
$ threads=25
$ ls -d raw.cluster.clean.mapping/* \
| rush -v ref=$ref -v j=$threads -v p='{}/{%}' \
'bwa mem -t {j} -M -a {ref} {p}_1.fq.gz {p}_2.fq.gz > {p}.sam; \
samtools view -bS {p}.sam > {p}.bam; \
samtools sort -T {p}.tmp -@ {j} {p}.bam -o {p}.sorted.bam; \
samtools index {p}.sorted.bam; \
samtools flagstat {p}.sorted.bam > {p}.sorted.bam.flagstat; \
/bin/rm {p}.bam {p}.sam;' \
-j 2 --verbose -c -C mapping.rush
@end verbatim
GNU @strong{parallel} would use a function:
@verbatim
$ ref=ref/xxx.fa
$ export ref
$ thr=25
$ export thr
$ bwa_sam() {
p="$1"
bam="$p".bam
sam="$p".sam
sortbam="$p".sorted.bam
bwa mem -t $thr -M -a $ref ${p}_1.fq.gz ${p}_2.fq.gz > "$sam"
samtools view -bS "$sam" > "$bam"
samtools sort -T ${p}.tmp -@ $thr "$bam" -o "$sortbam"
samtools index "$sortbam"
samtools flagstat "$sortbam" > "$sortbam".flagstat
/bin/rm "$bam" "$sam"
}
$ export -f bwa_sam
$ ls -d raw.cluster.clean.mapping/* |
parallel -j 2 --verbose --joblog mylog bwa_sam
@end verbatim
@node Other @strong{rush} features
@subsection Other @strong{rush} features
@strong{rush} has:
@itemize
@item @strong{awk -v} like custom defined variables (@strong{-v})
With GNU @strong{parallel} you would simply set a shell variable:
@verbatim
parallel 'v={}; echo "$v"' ::: foo
echo foo | rush -v v={} 'echo {v}'
@end verbatim
Also @strong{rush} does not like special chars. So these @strong{do not work}:
@verbatim
echo does not work | rush -v v=\" 'echo {v}'
echo "My brother's 12\" records" | rush -v v={} 'echo {v}'
@end verbatim
Whereas the corresponding GNU @strong{parallel} version works:
@verbatim
parallel 'v=\"; echo "$v"' ::: works
parallel 'v={}; echo "$v"' ::: "My brother's 12\" records"
@end verbatim
@item Exit on first error(s) (-e)
This is called @strong{--halt now,fail=1} (or shorter: @strong{--halt 2}) when
used with GNU @strong{parallel}.
@item Settable records sending to every command (@strong{-n}, default 1)
This is also called @strong{-n} in GNU @strong{parallel}.
@item Practical replacement strings
@table @asis
@item @{:@} remove any extension
@anchor{@{:@} remove any extension}
With GNU @strong{parallel} this can be emulated by:
@verbatim
parallel --plus echo '{/\..*/}' ::: foo.ext.bar.gz
@end verbatim
@item @{^suffix@}, remove suffix
@anchor{@{^suffix@}@comma{} remove suffix}
With GNU @strong{parallel} this can be emulated by:
@verbatim
parallel --plus echo '{%.bar.gz}' ::: foo.ext.bar.gz
@end verbatim
@item @{@@regexp@}, capture submatch using regular expression
@anchor{@{@@regexp@}@comma{} capture submatch using regular expression}
With GNU @strong{parallel} this can be emulated by:
@verbatim
parallel --rpl '{@(.*?)} /$$1/ and $_=$1;' \
echo '{@\d_(.*).gz}' ::: 1_foo.gz
@end verbatim
@item @{%.@}, @{%:@}, basename without extension
@anchor{@{%.@}@comma{} @{%:@}@comma{} basename without extension}
With GNU @strong{parallel} this can be emulated by:
@verbatim
parallel echo '{= s:.*/::;s/\..*// =}' ::: dir/foo.bar.gz
@end verbatim
And if you need it often, you define a @strong{--rpl} in
@strong{$HOME/.parallel/config}:
@verbatim
--rpl '{%.} s:.*/::;s/\..*//'
--rpl '{%:} s:.*/::;s/\..*//'
@end verbatim
Then you can use them as:
@verbatim
parallel echo {%.} {%:} ::: dir/foo.bar.gz
@end verbatim
@end table
@item Preset variable (macro)
E.g.
@verbatim
echo foosuffix | rush -v p={^suffix} 'echo {p}_new_suffix'
@end verbatim
With GNU @strong{parallel} this can be emulated by:
@verbatim
echo foosuffix |
parallel --plus 'p={%suffix}; echo ${p}_new_suffix'
@end verbatim
Opposite @strong{rush} GNU @strong{parallel} works fine if the input contains
double space, ' and ":
@verbatim
echo "1'6\" foosuffix" |
parallel --plus 'p={%suffix}; echo "${p}"_new_suffix'
@end verbatim
@item Commands of multi-lines
While you @emph{can} use multi-lined commands in GNU @strong{parallel}, to
improve readability GNU @strong{parallel} discourages the use of multi-line
commands. In most cases it can be written as a function:
@verbatim
seq 1 3 |
parallel --timeout 2 --joblog my.log 'sleep {}; echo {}; \
echo finish {}'
@end verbatim
Could be written as:
@verbatim
doit() {
sleep "$1"
echo "$1"
echo finish "$1"
}
export -f doit
seq 1 3 | parallel --timeout 2 --joblog my.log doit
@end verbatim
The failed commands can be resumed with:
@verbatim
seq 1 3 |
parallel --resume-failed --joblog my.log 'sleep {}; echo {};\
echo finish {}'
@end verbatim
@end itemize
https://github.com/shenwei356/rush
@node DIFFERENCES BETWEEN ClusterSSH AND GNU Parallel
@section DIFFERENCES BETWEEN ClusterSSH AND GNU Parallel
ClusterSSH solves a different problem than GNU @strong{parallel}.
ClusterSSH opens a terminal window for each computer and using a
master window you can run the same command on all the computers. This
is typically used for administrating several computers that are almost
identical.
GNU @strong{parallel} runs the same (or different) commands with different
arguments in parallel possibly using remote computers to help
computing. If more than one computer is listed in @strong{-S} GNU @strong{parallel} may
only use one of these (e.g. if there are 8 jobs to be run and one
computer has 8 cores).
GNU @strong{parallel} can be used as a poor-man's version of ClusterSSH:
@strong{parallel --nonall -S server-a,server-b do_stuff foo bar}
https://github.com/duncs/clusterssh
@node DIFFERENCES BETWEEN coshell AND GNU Parallel
@section DIFFERENCES BETWEEN coshell AND GNU Parallel
@strong{coshell} only accepts full commands on standard input. Any quoting
needs to be done by the user.
Commands are run in @strong{sh} so any @strong{bash}/@strong{tcsh}/@strong{zsh} specific
syntax will not work.
Output can be buffered by using @strong{-d}. Output is buffered in memory,
so big output can cause swapping and therefore be terrible slow or
even cause out of memory.
https://github.com/gdm85/coshell (Last checked: 2019-01)
@node DIFFERENCES BETWEEN spread AND GNU Parallel
@section DIFFERENCES BETWEEN spread AND GNU Parallel
@strong{spread} runs commands on all directories.
It can be emulated with GNU @strong{parallel} using this Bash function:
@verbatim
spread() {
_cmds() {
perl -e '$"=" && ";print "@ARGV"' "cd {}" "$@"
}
parallel $(_cmds "$@")'|| echo exit status $?' ::: */
}
@end verbatim
This works except for the @strong{--exclude} option.
(Last checked: 2017-11)
@node DIFFERENCES BETWEEN pyargs AND GNU Parallel
@section DIFFERENCES BETWEEN pyargs AND GNU Parallel
@strong{pyargs} deals badly with input containing spaces. It buffers stdout,
but not stderr. It buffers in RAM. @{@} does not work as replacement
string. It does not support running functions.
@strong{pyargs} does not support composed commands if run with @strong{--lines},
and fails on @strong{pyargs traceroute gnu.org fsf.org}.
@menu
* Examples::
@end menu
@node Examples
@subsection Examples
@verbatim
seq 5 | pyargs -P50 -L seq
seq 5 | parallel -P50 --lb seq
seq 5 | pyargs -P50 --mark -L seq
seq 5 | parallel -P50 --lb \
--tagstring OUTPUT'[{= $_=$job->replaced()=}]' seq
# Similar, but not precisely the same
seq 5 | parallel -P50 --lb --tag seq
seq 5 | pyargs -P50 --mark command
# Somewhat longer with GNU Parallel due to the special
# --mark formatting
cmd="$(echo "command" | parallel --shellquote)"
wrap_cmd() {
echo "MARK $cmd $@================================" >&3
echo "OUTPUT START[$cmd $@]:"
eval $cmd "$@"
echo "OUTPUT END[$cmd $@]"
}
(seq 5 | env_parallel -P2 wrap_cmd) 3>&1
# Similar, but not exactly the same
seq 5 | parallel -t --tag command
(echo '1 2 3';echo 4 5 6) | pyargs --stream seq
(echo '1 2 3';echo 4 5 6) | perl -pe 's/\n/ /' |
parallel -r -d' ' seq
# Similar, but not exactly the same
parallel seq ::: 1 2 3 4 5 6
@end verbatim
https://github.com/robertblackwell/pyargs (Last checked: 2019-01)
@node DIFFERENCES BETWEEN concurrently AND GNU Parallel
@section DIFFERENCES BETWEEN concurrently AND GNU Parallel
@strong{concurrently} runs jobs in parallel.
The output is prepended with the job number, and may be incomplete:
@verbatim
$ concurrently 'seq 100000' | (sleep 3;wc -l)
7165
@end verbatim
When pretty printing it caches output in memory. Output mixes by using
test MIX below whether or not output is cached.
There seems to be no way of making a template command and have
@strong{concurrently} fill that with different args. The full commands must
be given on the command line.
There is also no way of controlling how many jobs should be run in
parallel at a time - i.e. "number of jobslots". Instead all jobs are
simply started in parallel.
https://github.com/kimmobrunfeldt/concurrently (Last checked: 2019-01)
@node DIFFERENCES BETWEEN map(soveran) AND GNU Parallel
@section DIFFERENCES BETWEEN map(soveran) AND GNU Parallel
@strong{map} does not run jobs in parallel by default. The README suggests using:
@verbatim
... | map t 'sleep $t && say done &'
@end verbatim
But this fails if more jobs are run in parallel than the number of
available processes. Since there is no support for parallelization in
@strong{map} itself, the output also mixes:
@verbatim
seq 10 | map i 'echo start-$i && sleep 0.$i && echo end-$i &'
@end verbatim
The major difference is that GNU @strong{parallel} is built for parallelization
and @strong{map} is not. So GNU @strong{parallel} has lots of ways of dealing with the
issues that parallelization raises:
@itemize
@item Keep the number of processes manageable
@item Make sure output does not mix
@item Make Ctrl-C kill all running processes
@end itemize
Here are the 5 examples converted to GNU Parallel:
@verbatim
1$ ls *.c | map f 'foo $f'
1$ ls *.c | parallel foo
2$ ls *.c | map f 'foo $f; bar $f'
2$ ls *.c | parallel 'foo {}; bar {}'
3$ cat urls | map u 'curl -O $u'
3$ cat urls | parallel curl -O
4$ printf "1\n1\n1\n" | map t 'sleep $t && say done'
4$ printf "1\n1\n1\n" | parallel 'sleep {} && say done'
4$ parallel 'sleep {} && say done' ::: 1 1 1
5$ printf "1\n1\n1\n" | map t 'sleep $t && say done &'
5$ printf "1\n1\n1\n" | parallel -j0 'sleep {} && say done'
5$ parallel -j0 'sleep {} && say done' ::: 1 1 1
@end verbatim
https://github.com/soveran/map (Last checked: 2019-01)
@node DIFFERENCES BETWEEN loop AND GNU Parallel
@section DIFFERENCES BETWEEN loop AND GNU Parallel
@strong{loop} mixes stdout and stderr:
@verbatim
loop 'ls /no-such-file' >/dev/null
@end verbatim
@strong{loop}'s replacement string @strong{$ITEM} does not quote strings:
@verbatim
echo 'two spaces' | loop 'echo $ITEM'
@end verbatim
@strong{loop} cannot run functions:
@verbatim
myfunc() { echo joe; }
export -f myfunc
loop 'myfunc this fails'
@end verbatim
Some of the examples from https://github.com/Miserlou/Loop/ can be
emulated with GNU @strong{parallel}:
@verbatim
# A couple of functions will make the code easier to read
$ loopy() {
yes | parallel -uN0 -j1 "$@"
}
$ export -f loopy
$ time_out() {
parallel -uN0 -q --timeout "$@" ::: 1
}
$ match() {
perl -0777 -ne 'grep /'"$1"'/,$_ and print or exit 1'
}
$ export -f match
$ loop 'ls' --every 10s
$ loopy --delay 10s ls
$ loop 'touch $COUNT.txt' --count-by 5
$ loopy touch '{= $_=seq()*5 =}'.txt
$ loop --until-contains 200 -- \
./get_response_code.sh --site mysite.biz`
$ loopy --halt now,success=1 \
'./get_response_code.sh --site mysite.biz | match 200'
$ loop './poke_server' --for-duration 8h
$ time_out 8h loopy ./poke_server
$ loop './poke_server' --until-success
$ loopy --halt now,success=1 ./poke_server
$ cat files_to_create.txt | loop 'touch $ITEM'
$ cat files_to_create.txt | parallel touch {}
$ loop 'ls' --for-duration 10min --summary
# --joblog is somewhat more verbose than --summary
$ time_out 10m loopy --joblog my.log ./poke_server; cat my.log
$ loop 'echo hello'
$ loopy echo hello
$ loop 'echo $COUNT'
# GNU Parallel counts from 1
$ loopy echo {#}
# Counting from 0 can be forced
$ loopy echo '{= $_=seq()-1 =}'
$ loop 'echo $COUNT' --count-by 2
$ loopy echo '{= $_=2*(seq()-1) =}'
$ loop 'echo $COUNT' --count-by 2 --offset 10
$ loopy echo '{= $_=10+2*(seq()-1) =}'
$ loop 'echo $COUNT' --count-by 1.1
# GNU Parallel rounds 3.3000000000000003 to 3.3
$ loopy echo '{= $_=1.1*(seq()-1) =}'
$ loop 'echo $COUNT $ACTUALCOUNT' --count-by 2
$ loopy echo '{= $_=2*(seq()-1) =} {#}'
$ loop 'echo $COUNT' --num 3 --summary
# --joblog is somewhat more verbose than --summary
$ seq 3 | parallel --joblog my.log echo; cat my.log
$ loop 'ls -foobarbatz' --num 3 --summary
# --joblog is somewhat more verbose than --summary
$ seq 3 | parallel --joblog my.log -N0 ls -foobarbatz; cat my.log
$ loop 'echo $COUNT' --count-by 2 --num 50 --only-last
# Can be emulated by running 2 jobs
$ seq 49 | parallel echo '{= $_=2*(seq()-1) =}' >/dev/null
$ echo 50| parallel echo '{= $_=2*(seq()-1) =}'
$ loop 'date' --every 5s
$ loopy --delay 5s date
$ loop 'date' --for-duration 8s --every 2s
$ time_out 8s loopy --delay 2s date
$ loop 'date -u' --until-time '2018-05-25 20:50:00' --every 5s
$ seconds=$((`date -d 2019-05-25T20:50:00 +%s` - `date +%s`))s
$ time_out $seconds loopy --delay 5s date -u
$ loop 'echo $RANDOM' --until-contains "666"
$ loopy --halt now,success=1 'echo $RANDOM | match 666'
$ loop 'if (( RANDOM % 2 )); then
(echo "TRUE"; true);
else
(echo "FALSE"; false);
fi' --until-success
$ loopy --halt now,success=1 'if (( $RANDOM % 2 )); then
(echo "TRUE"; true);
else
(echo "FALSE"; false);
fi'
$ loop 'if (( RANDOM % 2 )); then
(echo "TRUE"; true);
else
(echo "FALSE"; false);
fi' --until-error
$ loopy --halt now,fail=1 'if (( $RANDOM % 2 )); then
(echo "TRUE"; true);
else
(echo "FALSE"; false);
fi'
$ loop 'date' --until-match "(\d{4})"
$ loopy --halt now,success=1 'date | match [0-9][0-9][0-9][0-9]'
$ loop 'echo $ITEM' --for red,green,blue
$ parallel echo ::: red green blue
$ cat /tmp/my-list-of-files-to-create.txt | loop 'touch $ITEM'
$ cat /tmp/my-list-of-files-to-create.txt | parallel touch
$ ls | loop 'cp $ITEM $ITEM.bak'; ls
$ ls | parallel cp {} {}.bak; ls
$ loop 'echo $ITEM | tr a-z A-Z' -i
$ parallel 'echo {} | tr a-z A-Z'
# Or more efficiently:
$ parallel --pipe tr a-z A-Z
$ loop 'echo $ITEM' --for "`ls`"
$ parallel echo {} ::: "`ls`"
$ ls | loop './my_program $ITEM' --until-success;
$ ls | parallel --halt now,success=1 ./my_program {}
$ ls | loop './my_program $ITEM' --until-fail;
$ ls | parallel --halt now,fail=1 ./my_program {}
$ ./deploy.sh;
loop 'curl -sw "%{http_code}" http://coolwebsite.biz' \
--every 5s --until-contains 200;
./announce_to_slack.sh
$ ./deploy.sh;
loopy --delay 5s --halt now,success=1 \
'curl -sw "%{http_code}" http://coolwebsite.biz | match 200';
./announce_to_slack.sh
$ loop "ping -c 1 mysite.com" --until-success; ./do_next_thing
$ loopy --halt now,success=1 ping -c 1 mysite.com; ./do_next_thing
$ ./create_big_file -o my_big_file.bin;
loop 'ls' --until-contains 'my_big_file.bin';
./upload_big_file my_big_file.bin
# inotifywait is a better tool to detect file system changes.
# It can even make sure the file is complete
# so you are not uploading an incomplete file
$ inotifywait -qmre MOVED_TO -e CLOSE_WRITE --format %w%f . |
grep my_big_file.bin
$ ls | loop 'cp $ITEM $ITEM.bak'
$ ls | parallel cp {} {}.bak
$ loop './do_thing.sh' --every 15s --until-success --num 5
$ parallel --retries 5 --delay 15s ::: ./do_thing.sh
@end verbatim
https://github.com/Miserlou/Loop/ (Last checked: 2018-10)
@node DIFFERENCES BETWEEN lorikeet AND GNU Parallel
@section DIFFERENCES BETWEEN lorikeet AND GNU Parallel
@strong{lorikeet} can run jobs in parallel. It does this based on a
dependency graph described in a file, so this is similar to @strong{make}.
https://github.com/cetra3/lorikeet (Last checked: 2018-10)
@node DIFFERENCES BETWEEN spp AND GNU Parallel
@section DIFFERENCES BETWEEN spp AND GNU Parallel
@strong{spp} can run jobs in parallel. @strong{spp} does not use a command
template to generate the jobs, but requires jobs to be in a
file. Output from the jobs mix.
https://github.com/john01dav/spp (Last checked: 2019-01)
@node DIFFERENCES BETWEEN paral AND GNU Parallel
@section DIFFERENCES BETWEEN paral AND GNU Parallel
@strong{paral} prints a lot of status information and stores the output from
the commands run into files. This means it cannot be used the middle
of a pipe like this
@verbatim
paral "echo this" "echo does not" "echo work" | wc
@end verbatim
Instead it puts the output into files named like
@strong{out_#_@emph{command}.out.log}. To get a very similar behaviour with GNU
@strong{parallel} use @strong{--results
'out_@{#@}_@{=s/[^\sa-z_0-9]//g;s/\s+/_/g=@}.log' --eta}
@strong{paral} only takes arguments on the command line and each argument
should be a full command. Thus it does not use command templates.
This limits how many jobs it can run in total, because they all need
to fit on a single command line.
@strong{paral} has no support for running jobs remotely.
The examples from @strong{README.markdown} and the corresponding command run
with GNU @strong{parallel} (@strong{--results
'out_@{#@}_@{=s/[^\sa-z_0-9]//g;s/\s+/_/g=@}.log' --eta} is omitted from
the GNU @strong{parallel} command):
@verbatim
paral "command 1" "command 2 --flag" "command arg1 arg2"
parallel ::: "command 1" "command 2 --flag" "command arg1 arg2"
paral "sleep 1 && echo c1" "sleep 2 && echo c2" \
"sleep 3 && echo c3" "sleep 4 && echo c4" "sleep 5 && echo c5"
parallel ::: "sleep 1 && echo c1" "sleep 2 && echo c2" \
"sleep 3 && echo c3" "sleep 4 && echo c4" "sleep 5 && echo c5"
# Or shorter:
parallel "sleep {} && echo c{}" ::: {1..5}
paral -n=0 "sleep 5 && echo c5" "sleep 4 && echo c4" \
"sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1"
parallel ::: "sleep 5 && echo c5" "sleep 4 && echo c4" \
"sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1"
# Or shorter:
parallel -j0 "sleep {} && echo c{}" ::: 5 4 3 2 1
paral -n=1 "sleep 5 && echo c5" "sleep 4 && echo c4" \
"sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1"
parallel -j1 "sleep {} && echo c{}" ::: 5 4 3 2 1
paral -n=2 "sleep 5 && echo c5" "sleep 4 && echo c4" \
"sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1"
parallel -j2 "sleep {} && echo c{}" ::: 5 4 3 2 1
paral -n=5 "sleep 5 && echo c5" "sleep 4 && echo c4" \
"sleep 3 && echo c3" "sleep 2 && echo c2" "sleep 1 && echo c1"
parallel -j5 "sleep {} && echo c{}" ::: 5 4 3 2 1
paral -n=1 "echo a && sleep 0.5 && echo b && sleep 0.5 && \
echo c && sleep 0.5 && echo d && sleep 0.5 && \
echo e && sleep 0.5 && echo f && sleep 0.5 && \
echo g && sleep 0.5 && echo h"
parallel ::: "echo a && sleep 0.5 && echo b && sleep 0.5 && \
echo c && sleep 0.5 && echo d && sleep 0.5 && \
echo e && sleep 0.5 && echo f && sleep 0.5 && \
echo g && sleep 0.5 && echo h"
@end verbatim
https://github.com/amattn/paral (Last checked: 2019-01)
@node DIFFERENCES BETWEEN concurr AND GNU Parallel
@section DIFFERENCES BETWEEN concurr AND GNU Parallel
@strong{concurr} is built to run jobs in parallel using a client/server
model.
The examples from @strong{README.md}:
@verbatim
concurr 'echo job {#} on slot {%}: {}' : arg1 arg2 arg3 arg4
parallel 'echo job {#} on slot {%}: {}' ::: arg1 arg2 arg3 arg4
concurr 'echo job {#} on slot {%}: {}' :: file1 file2 file3
parallel 'echo job {#} on slot {%}: {}' :::: file1 file2 file3
concurr 'echo {}' < input_file
parallel 'echo {}' < input_file
cat file | concurr 'echo {}'
cat file | parallel 'echo {}'
@end verbatim
@strong{concurr} deals badly empty input files and with output larger than
64 KB.
https://github.com/mmstick/concurr (Last checked: 2019-01)
@node DIFFERENCES BETWEEN lesser-parallel AND GNU Parallel
@section DIFFERENCES BETWEEN lesser-parallel AND GNU Parallel
@strong{lesser-parallel} is the inspiration for @strong{parallel --embed}. Both
@strong{lesser-parallel} and @strong{parallel --embed} define bash functions that
can be included as part of a bash script to run jobs in parallel.
@strong{lesser-parallel} implements a few of the replacement strings, but
hardly any options, whereas @strong{parallel --embed} gives you the full
GNU @strong{parallel} experience.
https://github.com/kou1okada/lesser-parallel (Last checked: 2019-01)
@node DIFFERENCES BETWEEN npm-parallel AND GNU Parallel
@section DIFFERENCES BETWEEN npm-parallel AND GNU Parallel
@strong{npm-parallel} can run npm tasks in parallel.
There are no examples and very little documentation, so it is hard to
compare to GNU @strong{parallel}.
https://github.com/spion/npm-parallel (Last checked: 2019-01)
@node DIFFERENCES BETWEEN machma AND GNU Parallel
@section DIFFERENCES BETWEEN machma AND GNU Parallel
@strong{machma} runs tasks in parallel. It gives time stamped
output. It buffers in RAM. The examples from README.md:
@verbatim
find . -iname '*.jpg' |
machma -- mogrify -resize 1200x1200 -filter Lanczos {}
find . -iname '*.jpg' |
parallel mogrify -resize 1200x1200 -filter Lanczos {}
cat /tmp/ips | machma -p 2 -- ping -c 2 -q {}
cat /tmp/ips | parallel -j 2 --tag --line-buffer ping -c 2 -q {}
cat /tmp/ips |
machma -- sh -c 'ping -c 2 -q $0 > /dev/null && echo alive' {}
cat /tmp/ips |
parallel --tag 'ping -c 2 -q {} > /dev/null && echo alive'
find . -iname '*.jpg' |
machma --timeout 5s -- mogrify -resize 1200x1200 -filter Lanczos {}
find . -iname '*.jpg' |
parallel --timeout 5s mogrify -resize 1200x1200 -filter Lanczos {}
find . -iname '*.jpg' -print0 |
machma --null -- mogrify -resize 1200x1200 -filter Lanczos {}
find . -iname '*.jpg' -print0 |
parallel --null mogrify -resize 1200x1200 -filter Lanczos {}
@end verbatim
https://github.com/fd0/machma (Last checked: 2019-01)
@node DIFFERENCES BETWEEN interlace AND GNU Parallel
@section DIFFERENCES BETWEEN interlace AND GNU Parallel
@strong{interlace} is built for network analysis to run network tools in parallel.
@strong{interface} does not buffer output, so output from different jobs mixes.
Using @strong{prips} most of the examples from
https://github.com/codingo/Interlace can be run with GNU @strong{parallel}:
@verbatim
interlace -tL ./targets.txt -threads 5 \
-c "nikto --host _target_ > ./_target_-nikto.txt" -v
parallel -a targets.txt -P5 nikto --host {} > ./{}_-nikto.txt
interlace -tL ./targets.txt -threads 5 -c \
"nikto --host _target_:_port_ > ./_target_-_port_-nikto.txt" \
-p 80,443 -v
parallel -P5 nikto --host {1}:{2} > ./{1}-{2}-nikto.txt \
:::: targets.txt ::: 80 443
commands.txt:
nikto --host _target_:_port_ > _output_/_target_-nikto.txt
sslscan _target_:_port_ > _output_/_target_-sslscan.txt
testssl.sh _target_:_port_ > _output_/_target_-testssl.txt
interlace -t example.com -o ~/Engagements/example/ \
-cL ./commands.txt -p 80,443
_nikto() {
nikto --host "$1:$2"
}
_sslscan() {
sslscan "$1:$2"
}
_testssl() {
testssl.sh "$1:$2"
}
export -f _nikto
export -f _sslscan
export -f _testssl
parallel --results ~/Engagements/example/{2}:{3}{1} \
::: _nikto _sslscan _testssl ::: example.com ::: 80 443
interlace -t 192.168.12.0/24 -c "vhostscan _target_ \
-oN _output_/_target_-vhosts.txt" -o ~/scans/ -threads 50
prips 192.168.12.0/24 |
parallel -P50 vhostscan {} -oN ~/scans/{}-vhosts.txt
interlace -t 192.168.12.* -c "vhostscan _target_ \
-oN _output_/_target_-vhosts.txt" -o ~/scans/ -threads 50
# Glob is not supported in prips
prips 192.168.12.0/24 |
parallel -P50 vhostscan {} -oN ~/scans/{}-vhosts.txt
interlace -t 192.168.12.1-15 -c \
"vhostscan _target_ -oN _output_/_target_-vhosts.txt" \
-o ~/scans/ -threads 50
# Dash notation is not supported in prips
prips 192.168.12.1 192.168.12.15 |
parallel -P50 vhostscan {} -oN ~/scans/{}-vhosts.txt
interlace -tL ./target-list.txt -c \
"vhostscan -t _target_ -oN _output_/_target_-vhosts.txt" \
-o ~/scans/ -threads 50
cat ./target-list.txt |
parallel -P50 vhostscan -t {} -oN ~/scans/{}-vhosts.txt
./vhosts-commands.txt -tL ./target-list.txt:
vhostscan -t $target -oN _output_/_target_-vhosts.txt
interlace -cL ./vhosts-commands.txt -tL ./target-list.txt \
-threads 50 -o ~/scans
./vhosts-commands.txt -tL ./target-list.txt:
vhostscan -t "$1" -oN "$2"
parallel -P50 ./vhosts-commands.txt {} ~/scans/{} \
:::: ./target-list.txt
interlace -t 192.168.12.0/24 -e 192.168.12.0/26 -c \
"vhostscan _target_ -oN _output_/_target_-vhosts.txt" \
-o ~/scans/ -threads 50
prips 192.168.12.0/24 | grep -xv -Ff <(prips 192.168.12.0/26) |
parallel -P50 vhostscan {} -oN ~/scans/{}-vhosts.txt
@end verbatim
https://github.com/codingo/Interlace (Last checked: 2019-02)
@node DIFFERENCES BETWEEN otonvm Parallel AND GNU Parallel
@section DIFFERENCES BETWEEN otonvm Parallel AND GNU Parallel
I have been unable to get the code to run at all. It seems unfinished.
https://github.com/otonvm/Parallel (Last checked: 2019-02)
@node DIFFERENCES BETWEEN k-bx par AND GNU Parallel
@section DIFFERENCES BETWEEN k-bx par AND GNU Parallel
@strong{par} requires Haskell to work. This limits the number of platforms
this can work on.
@strong{par} does line buffering in memory. The memory usage is 3x the
longest line (compared to 1x for @strong{parallel --lb}). Commands must be
given as arguments. There is no template.
These are the examples from https://github.com/k-bx/par with the
corresponding GNU @strong{parallel} command.
@verbatim
par "echo foo; sleep 1; echo foo; sleep 1; echo foo" \
"echo bar; sleep 1; echo bar; sleep 1; echo bar" && echo "success"
parallel --lb ::: "echo foo; sleep 1; echo foo; sleep 1; echo foo" \
"echo bar; sleep 1; echo bar; sleep 1; echo bar" && echo "success"
par "echo foo; sleep 1; foofoo" \
"echo bar; sleep 1; echo bar; sleep 1; echo bar" && echo "success"
parallel --lb --halt 1 ::: "echo foo; sleep 1; foofoo" \
"echo bar; sleep 1; echo bar; sleep 1; echo bar" && echo "success"
par "PARPREFIX=[fooechoer] echo foo" "PARPREFIX=[bar] echo bar"
parallel --lb --colsep , --tagstring {1} {2} \
::: "[fooechoer],echo foo" "[bar],echo bar"
par --succeed "foo" "bar" && echo 'wow'
parallel "foo" "bar"; true && echo 'wow'
@end verbatim
https://github.com/k-bx/par (Last checked: 2019-02)
@node DIFFERENCES BETWEEN parallelshell AND GNU Parallel
@section DIFFERENCES BETWEEN parallelshell AND GNU Parallel
@strong{parallelshell} does not allow for composed commands:
@verbatim
# This does not work
parallelshell 'echo foo;echo bar' 'echo baz;echo quuz'
@end verbatim
Instead you have to wrap that in a shell:
@verbatim
parallelshell 'sh -c "echo foo;echo bar"' 'sh -c "echo baz;echo quuz"'
@end verbatim
It buffers output in RAM. All commands must be given on the command
line and all commands are started in parallel at the same time. This
will cause the system to freeze if there are so many jobs that there
is not enough memory to run them all at the same time.
https://github.com/keithamus/parallelshell (Last checked: 2019-02)
https://github.com/darkguy2008/parallelshell (Last checked: 2019-03)
@node DIFFERENCES BETWEEN shell-executor AND GNU Parallel
@section DIFFERENCES BETWEEN shell-executor AND GNU Parallel
@strong{shell-executor} does not allow for composed commands:
@verbatim
# This does not work
sx 'echo foo;echo bar' 'echo baz;echo quuz'
@end verbatim
Instead you have to wrap that in a shell:
@verbatim
sx 'sh -c "echo foo;echo bar"' 'sh -c "echo baz;echo quuz"'
@end verbatim
It buffers output in RAM. All commands must be given on the command
line and all commands are started in parallel at the same time. This
will cause the system to freeze if there are so many jobs that there
is not enough memory to run them all at the same time.
https://github.com/royriojas/shell-executor (Last checked: 2019-02)
@node DIFFERENCES BETWEEN non-GNU par AND GNU Parallel
@section DIFFERENCES BETWEEN non-GNU par AND GNU Parallel
@strong{par} buffers in memory to avoid mixing of jobs. It takes 1s per 1
million output lines.
@strong{par} needs to have all commands before starting the first job. The
jobs are read from stdin (standard input) so any quoting will have to
be done by the user.
Stdout (standard output) is prepended with o:. Stderr (standard error)
is sendt to stdout (standard output) and prepended with e:.
For short jobs with little output @strong{par} is 20% faster than GNU
@strong{parallel} and 60% slower than @strong{xargs}.
http://savannah.nongnu.org/projects/par (Last checked: 2019-02)
@node DIFFERENCES BETWEEN fd AND GNU Parallel
@section DIFFERENCES BETWEEN fd AND GNU Parallel
@strong{fd} does not support composed commands, so commands must be wrapped
in @strong{sh -c}.
It buffers output in RAM.
It only takes file names from the filesystem as input (similar to @strong{find}).
https://github.com/sharkdp/fd (Last checked: 2019-02)
@node DIFFERENCES BETWEEN lateral AND GNU Parallel
@section DIFFERENCES BETWEEN lateral AND GNU Parallel
@strong{lateral} is very similar to @strong{sem}: It takes a single command and
runs it in the background. The design means that output from parallel
running jobs may mix. If it dies unexpectly it leaves a socket in
~/.lateral/socket.PID.
@strong{lateral} deals badly with too long command lines. This makes the
@strong{lateral} server crash:
@verbatim
lateral run echo `seq 100000| head -c 1000k`
@end verbatim
Any options will be read by @strong{lateral} so this does not work
(@strong{lateral} interprets the @strong{-l}):
@verbatim
lateral run ls -l
@end verbatim
Composed commands do not work:
@verbatim
lateral run pwd ';' ls
@end verbatim
Functions do not work:
@verbatim
myfunc() { echo a; }
export -f myfunc
lateral run myfunc
@end verbatim
Running @strong{emacs} in the terminal causes the parent shell to die:
@verbatim
echo '#!/bin/bash' > mycmd
echo emacs -nw >> mycmd
chmod +x mycmd
lateral start
lateral run ./mycmd
@end verbatim
Here are the examples from https://github.com/akramer/lateral with the
corresponding GNU @strong{sem} and GNU @strong{parallel} commands:
@verbatim
1$ lateral start
1$ for i in $(cat /tmp/names); do
1$ lateral run -- some_command $i
1$ done
1$ lateral wait
1$
1$ for i in $(cat /tmp/names); do
1$ sem some_command $i
1$ done
1$ sem --wait
1$
1$ parallel some_command :::: /tmp/names
2$ lateral start
2$ for i in $(seq 1 100); do
2$ lateral run -- my_slow_command < workfile$i > /tmp/logfile$i
2$ done
2$ lateral wait
2$
2$ for i in $(seq 1 100); do
2$ sem my_slow_command < workfile$i > /tmp/logfile$i
2$ done
2$ sem --wait
2$
2$ parallel 'my_slow_command < workfile{} > /tmp/logfile{}' \
::: {1..100}
3$ lateral start -p 0 # yup, it will just queue tasks
3$ for i in $(seq 1 100); do
3$ lateral run -- command_still_outputs_but_wont_spam inputfile$i
3$ done
3$ # command output spam can commence
3$ lateral config -p 10; lateral wait
3$
3$ for i in $(seq 1 100); do
3$ echo "command inputfile$i" >> joblist
3$ done
3$ parallel -j 10 :::: joblist
3$
3$ echo 1 > /tmp/njobs
3$ parallel -j /tmp/njobs command inputfile{} \
::: {1..100} &
3$ echo 10 >/tmp/njobs
3$ wait
@end verbatim
https://github.com/akramer/lateral (Last checked: 2019-03)
@node DIFFERENCES BETWEEN with-this AND GNU Parallel
@section DIFFERENCES BETWEEN with-this AND GNU Parallel
The examples from https://github.com/amritb/with-this.git and the
corresponding GNU @strong{parallel} command:
@verbatim
with -v "$(cat myurls.txt)" "curl -L this"
parallel curl -L ::: myurls.txt
with -v "$(cat myregions.txt)" \
"aws --region=this ec2 describe-instance-status"
parallel aws --region={} ec2 describe-instance-status \
:::: myregions.txt
with -v "$(ls)" "kubectl --kubeconfig=this get pods"
ls | parallel kubectl --kubeconfig={} get pods
with -v "$(ls | grep config)" "kubectl --kubeconfig=this get pods"
ls | grep config | parallel kubectl --kubeconfig={} get pods
with -v "$(echo {1..10})" "echo 123"
parallel -N0 echo 123 ::: {1..10}
@end verbatim
Stderr is merged with stdout. @strong{with-this} buffers in RAM. It uses 3x
the output size, so you cannot have output larger than 1/3rd the
amount of RAM. The input values cannot contain spaces. Composed
commands do not work.
@strong{with-this} gives some additional information, so the output has to
be cleaned before piping it to the next command.
https://github.com/amritb/with-this.git (Last checked: 2019-03)
@node Todo
@section Todo
Url for spread
https://github.com/reggi/pkgrun
https://github.com/benoror/better-npm-run - not obvious how to use
https://github.com/bahmutov/with-package
https://github.com/xuchenCN/go-pssh
https://github.com/flesler/parallel
https://github.com/Julian/Verge
@node TESTING OTHER TOOLS
@chapter TESTING OTHER TOOLS
There are certain issues that are very common on parallelizing
tools. Here are a few stress tests. Be warned: If the tool is badly
coded it may overload your machine.
@menu
* MIX@asis{:} Output mixes::
* STDERRMERGE@asis{:} Stderr is merged with stdout::
* RAM@asis{:} Output limited by RAM::
* DISKFULL@asis{:} Incomplete data if /tmp runs full::
* CLEANUP@asis{:} Leaving tmp files at unexpected death::
* SPCCHAR@asis{:} Dealing badly with special file names.::
* COMPOSED@asis{:} Composed commands do not work::
* ONEREP@asis{:} Only one replacement string allowed::
* INPUTSIZE@asis{:} Length of input should not be limited::
* NUMWORDS@asis{:} Speed depends on number of words::
@end menu
@node MIX: Output mixes
@section MIX: Output mixes
Output from 2 jobs should not mix. If the output is not used, this
does not matter; but if the output @emph{is} used then it is important
that you do not get half a line from one job followed by half a line
from another job.
If the tool does not buffer, output will most likely mix now and then.
This test stresses whether output mixes.
@verbatim
#!/bin/bash
paralleltool="parallel -j0"
cat <<-EOF > mycommand
#!/bin/bash
# If a, b, c, d, e, and f mix: Very bad
perl -e 'print STDOUT "a"x3000_000," "'
perl -e 'print STDERR "b"x3000_000," "'
perl -e 'print STDOUT "c"x3000_000," "'
perl -e 'print STDERR "d"x3000_000," "'
perl -e 'print STDOUT "e"x3000_000," "'
perl -e 'print STDERR "f"x3000_000," "'
echo
echo >&2
EOF
chmod +x mycommand
# Run 30 jobs in parallel
seq 30 |
$paralleltool ./mycommand > >(tr -s abcdef) 2> >(tr -s abcdef >&2)
# 'a c e' and 'b d f' should always stay together
# and there should only be a single line per job
@end verbatim
@node STDERRMERGE: Stderr is merged with stdout
@section STDERRMERGE: Stderr is merged with stdout
Output from stdout and stderr should not be merged, but kept separated.
This test shows whether stdout is mixed with stderr.
@verbatim
#!/bin/bash
paralleltool="parallel -j0"
cat <<-EOF > mycommand
#!/bin/bash
echo stdout
echo stderr >&2
echo stdout
echo stderr >&2
EOF
chmod +x mycommand
# Run one job
echo |
$paralleltool ./mycommand > stdout 2> stderr
cat stdout
cat stderr
@end verbatim
@node RAM: Output limited by RAM
@section RAM: Output limited by RAM
Some tools cache output in RAM. This makes them extremely slow if the
output is bigger than physical memory and crash if the output is
bigger than the virtual memory.
@verbatim
#!/bin/bash
paralleltool="parallel -j0"
cat <<'EOF' > mycommand
#!/bin/bash
# Generate 1 GB output
yes "`perl -e 'print \"c\"x30_000'`" | head -c 1G
EOF
chmod +x mycommand
# Run 20 jobs in parallel
# Adjust 20 to be > physical RAM and < free space on /tmp
seq 20 | time $paralleltool ./mycommand | wc -c
@end verbatim
@node DISKFULL: Incomplete data if /tmp runs full
@section DISKFULL: Incomplete data if /tmp runs full
If caching is done on disk, the disk can run full during the run. Not
all programs discover this. GNU Parallel discovers it, if it stays
full for at least 2 seconds.
@verbatim
#!/bin/bash
paralleltool="parallel -j0"
# This should be a dir with less than 100 GB free space
smalldisk=/tmp/shm/parallel
TMPDIR="$smalldisk"
export TMPDIR
max_output() {
# Force worst case scenario:
# Make GNU Parallel only check once per second
sleep 10
# Generate 100 GB to fill $TMPDIR
# Adjust if /tmp is bigger than 100 GB
yes | head -c 100G >$TMPDIR/$$
# Generate 10 MB output that will not be buffered due to full disk
perl -e 'print "X"x10_000_000' | head -c 10M
echo This part is missing from incomplete output
sleep 2
rm $TMPDIR/$$
echo Final output
}
export -f max_output
seq 10 | $paralleltool max_output | tr -s X
@end verbatim
@node CLEANUP: Leaving tmp files at unexpected death
@section CLEANUP: Leaving tmp files at unexpected death
Some tools do not clean up tmp files if they are killed. If the tool
buffers on disk, they may not clean up, if they are killed.
@verbatim
#!/bin/bash
paralleltool=parallel
ls /tmp >/tmp/before
seq 10 | $paralleltool sleep &
pid=$!
# Give the tool time to start up
sleep 1
# Kill it without giving it a chance to cleanup
kill -9 $!
# Should be empty: No files should be left behind
diff <(ls /tmp) /tmp/before
@end verbatim
@node SPCCHAR: Dealing badly with special file names.
@section SPCCHAR: Dealing badly with special file names.
It is not uncommon for users to create files like:
@verbatim
My brother's 12" *** record (costs $$$).jpg
@end verbatim
Some tools break on this.
@verbatim
#!/bin/bash
paralleltool=parallel
touch "My brother's 12\" *** record (costs \$\$\$).jpg"
ls My*jpg | $paralleltool ls -l
@end verbatim
@node COMPOSED: Composed commands do not work
@section COMPOSED: Composed commands do not work
Some tools require you to wrap composed commands into @strong{bash -c}.
@verbatim
echo bar | $paralleltool echo foo';' echo {}
@end verbatim
@node ONEREP: Only one replacement string allowed
@section ONEREP: Only one replacement string allowed
Some tools can only insert the argument once.
@verbatim
echo bar | $paralleltool echo {} foo {}
@end verbatim
@node INPUTSIZE: Length of input should not be limited
@section INPUTSIZE: Length of input should not be limited
Some tools limit the length of the input lines artificially with no good
reason. GNU @strong{parallel} does not:
@verbatim
perl -e 'print "foo."."x"x100_000_000' | parallel echo {.}
@end verbatim
GNU @strong{parallel} limits the command to run to 128 KB due to execve(1):
@verbatim
perl -e 'print "x"x131_000' | parallel echo {} | wc
@end verbatim
@node NUMWORDS: Speed depends on number of words
@section NUMWORDS: Speed depends on number of words
Some tools become very slow if output lines have many words.
@verbatim
#!/bin/bash
paralleltool=parallel
cat <<-EOF > mycommand
#!/bin/bash
# 10 MB of lines with 1000 words
yes "`seq 1000`" | head -c 10M
EOF
chmod +x mycommand
# Run 30 jobs in parallel
seq 30 | time $paralleltool -j0 ./mycommand > /dev/null
@end verbatim
@node AUTHOR
@chapter AUTHOR
When using GNU @strong{parallel} for a publication please cite:
O. Tange (2011): GNU Parallel - The Command-Line Power Tool, ;login:
The USENIX Magazine, February 2011:42-47.
This helps funding further development; and it won't cost you a cent.
If you pay 10000 EUR you should feel free to use GNU Parallel without citing.
Copyright (C) 2007-10-18 Ole Tange, http://ole.tange.dk
Copyright (C) 2008-2010 Ole Tange, http://ole.tange.dk
Copyright (C) 2010-2019 Ole Tange, http://ole.tange.dk and Free
Software Foundation, Inc.
Parts of the manual concerning @strong{xargs} compatibility is inspired by
the manual of @strong{xargs} from GNU findutils 4.4.2.
@node LICENSE
@chapter LICENSE
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
at your option any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
@menu
* Documentation license I::
* Documentation license II::
@end menu
@node Documentation license I
@section Documentation license I
Permission is granted to copy, distribute and/or modify this documentation
under the terms of the GNU Free Documentation License, Version 1.3 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
Texts. A copy of the license is included in the file fdl.txt.
@node Documentation license II
@section Documentation license II
You are free:
@table @asis
@item @strong{to Share}
@anchor{@strong{to Share}}
to copy, distribute and transmit the work
@item @strong{to Remix}
@anchor{@strong{to Remix}}
to adapt the work
@end table
Under the following conditions:
@table @asis
@item @strong{Attribution}
@anchor{@strong{Attribution}}
You must attribute the work in the manner specified by the author or
licensor (but not in any way that suggests that they endorse you or
your use of the work).
@item @strong{Share Alike}
@anchor{@strong{Share Alike}}
If you alter, transform, or build upon this work, you may distribute
the resulting work only under the same, similar or a compatible
license.
@end table
With the understanding that:
@table @asis
@item @strong{Waiver}
@anchor{@strong{Waiver}}
Any of the above conditions can be waived if you get permission from
the copyright holder.
@item @strong{Public Domain}
@anchor{@strong{Public Domain}}
Where the work or any of its elements is in the public domain under
applicable law, that status is in no way affected by the license.
@item @strong{Other Rights}
@anchor{@strong{Other Rights}}
In no way are any of the following rights affected by the license:
@itemize
@item Your fair dealing or fair use rights, or other applicable
copyright exceptions and limitations;
@item The author's moral rights;
@item Rights other persons may have either in the work itself or in
how the work is used, such as publicity or privacy rights.
@end itemize
@end table
@table @asis
@item @strong{Notice}
@anchor{@strong{Notice}}
For any reuse or distribution, you must make clear to others the
license terms of this work.
@end table
A copy of the full license is included in the file as cc-by-sa.txt.
@node DEPENDENCIES
@chapter DEPENDENCIES
GNU @strong{parallel} uses Perl, and the Perl modules Getopt::Long,
IPC::Open3, Symbol, IO::File, POSIX, and File::Temp. For remote usage
it also uses rsync with ssh.
@node SEE ALSO
@chapter SEE ALSO
@strong{find}(1), @strong{xargs}(1), @strong{make}(1), @strong{pexec}(1), @strong{ppss}(1),
@strong{xjobs}(1), @strong{prll}(1), @strong{dxargs}(1), @strong{mdm}(1)
@bye