1PARALLEL(1)                        moreutils                       PARALLEL(1)
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NAME

6       parallel - run programs in parallel
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SYNOPSIS

9       parallel [options] [command]-- [argument ...]
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11       parallel [options]-- [command ...]
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DESCRIPTION

14       parallel runs the specified command, passing it a single one of the
15       specified arguments. This is repeated for each argument. Jobs may be
16       run in parallel. The default is to run one job per CPU.
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18       If no command is specified before the --, the commands after it are
19       instead run in parallel.
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OPTIONS

22       -j maxjobs
23           Use to limit the number of jobs that are run at the same time.
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25       -l maxload
26           Wait as needed to avoid starting new jobs when the system's load
27           average is not below the specified limit.
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29       -i
30           Normally the command is passed the argument at the end of its
31           command line. With this option, any instances of "{}" in the
32           command are replaced with the argument.
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34       -n
35           Number of arguments to pass to a command at a time. Default is 1.
36           Incompatible with -i
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EXAMPLE

39       parallel sh -c "echo hi; sleep 2; echo bye" -- 1 2 3
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41       This runs three subshells that each print a message, delay, and print
42       another message. If your system has multiple CPUs, parallel will run
43       some of the jobs in parallel, which should be clear from the order the
44       messages are output.
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46       parallel -j 3 ufraw -o processed -- *.NEF
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48       This runs three ufraw processes at the same time until all of the NEF
49       files have been processed.
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51       parallel -j 3 -- ls df "echo hi"
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53       This runs three independent commands in parallel.
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EXIT STATUS

56       Its exit status is the combination of the exit statuses of each command
57       ran, ORed together. (Thus, if any one command exits nonzero, parallel
58       as a whole will exit nonzero.)
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NOTES

61       All output to stdout and stderr is serialised through a corresponding
62       internal pipe, in order to prevent annoying concurrent output
63       behaviour. Note that serialisation is not done on any other file
64       descriptors and file position based access to a nonstandard file
65       descriptor might have unexpected results.
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AUTHOR

68       Tollef Fog Heen
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72moreutils                         2009-07-02                       PARALLEL(1)