parset - set shell variables in parallel
parset variablename [options for GNU Parallel]
env_parset variablename [options for GNU Parallel]
parset is a shell function that puts the output from GNU parallel into shell variables.
env_parset is a shell function that puts the output from env_parallel into shell variables.
The parset and env_parset functions are defined as part of env_parallel.
If variablename is a single variable name, this will be treated as the destination variable and made into an array.
If variablename contains multiple names separated by ',' or space, the names will be the destination variables.
Same as GNU parallel, but they are put after the destination variable.
Put output into myarray:
parset myarray seq 3 ::: 4 5 6
echo "${myarray[1]}"
Put output into vars $seq, $pwd, $ls:
parset "seq pwd ls" ::: "seq 10" pwd ls
echo "$ls"
Put output into vars $seq, $pwd, $ls:
into_vars=(seq pwd ls)
parset "${into_vars[*]}" ::: "seq 10" pwd ls
echo "$ls"
The commands to run can be an array:
cmd=("echo first" "echo '<<joe \"double space\" cartoon>>'" "pwd")
parset data ::: "${cmd[@]}"
echo "${data[1]}"
echo "${data[2]}"
parset can not be part of a pipe. In particular this means it cannot read anything from standard input (stdin) or write to a pipe:
seq 10 | parset res echo Does not work
but must instead use a tempfile:
seq 10 > parallel_input
parset res echo :::: parallel_input
echo "${res[1]}"
echo "${res[9]}"
or a FIFO:
mkfifo input_fifo
seq 30 > input_fifo &
parset res echo :::: input_fifo
echo "${res[1]}"
echo "${res[29]}"
or Bash/Zsh/Ksh process substitution:
parset res echo :::: <(seq 100)
echo "${res[1]}"
echo "${res[99]}"
Put this in the relevant $HOME/.bashrc or $HOME/.zshenv or $HOME/.kshrc:
. `which env_parallel.bash`
. `which env_parallel.zsh`
source `which env_parallel.ksh`
E.g. by doing:
echo '. `which env_parallel.bash`' >> $HOME/.bashrc
echo '. `which env_parallel.zsh`' >> $HOME/.zshenv
echo 'source `which env_parallel.ksh`' >> $HOME/.kshrc
or by doing:
env_parallel --install
ash does not support arrays.
Put output into vars $seq, $pwd, $ls:
parset "seq pwd ls" ::: "seq 10" pwd ls
echo "$ls"
parset can not be part of a pipe. In particular this means it cannot read anything from standard input (stdin) or write to a pipe:
seq 3 | parset res1,res2,res3 echo Does not work
but must instead use a tempfile:
seq 3 > parallel_input
parset res1,res2,res3 echo :::: parallel_input
echo "$res1"
echo "$res2"
echo "$res3"
or a FIFO:
mkfifo input_fifo
seq 3 > input_fifo &
parset res1,res2,res3 echo :::: input_fifo
echo "$res1"
echo "$res2"
echo "$res3"
Put the relevant one of these into $HOME/.profile:
. `which env_parallel.sh`
. `which env_parallel.ash`
. `which env_parallel.dash`
E.g. by doing:
echo '. `which env_parallel.ash`' >> $HOME/.bashrc
or by doing:
env_parallel --install
Same as GNU parallel.
When using GNU 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) 2008,2009,2010 Ole Tange, http://ole.tange.dk
Copyright (C) 2010,2011,2012,2013,2014,2015,2016,2017,2018 Ole Tange, http://ole.tange.dk and Free Software Foundation, Inc.
Copyright (C) 2016 Ole Tange and Free Software Foundation, Inc.
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parset uses GNU parallel.
parallel(1), env_parallel(1), bash(1).