loop

Note: loop has been deprecated in favor of the nicer looper.

This software is owned by The university of California, Irvine, and is not distributed under any version of the GPL. GPL is a fine series of licenses, but the owners of the software need it to be distributed under these terms.

Loop is a simple program that allows you to control the degree of parallelism used in running a bunch of programs.

You can download it here.

We've been using it for years with good results.

Usage is like:

seki-strombrg> loop
usage:
/dcslib/allsys/etc/loop -d save directory
/dcslib/allsys/etc/loop -n max concurrent proc
/dcslib/allsys/etc/loop -c command to execute
/dcslib/allsys/etc/loop -v (verbose)
stdin should consist of filename arguments
for each command to execute
Sun Jan 01 11:06:37

Example usage (from memory) might look like:

mkdir -p /tmp/savedir
rm /tmp/savedir/*
cat /tmp/hostname-list-one-host-per-line | sed 's/^$.*$$/\1 \1/' | loop -d /tmp/savedir -n 20 -c 'uname -n' -v
/tmp/savedir should then have one file per host, each containing the results from the command on each host. Then review the results with something like:
- vi /tmp/savedir/* # look at all the files
- vi $(ls /tmp/savedir | equivs2 -s | awk ' { print $1 } ') # only look at a single copy of any files that have the same content

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Timestamp: 2024-04-23 21:39:36 PDT

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