Name
run-one - run just one instance at a time of some command and unique set of arguments (useful for cronjobs, eg) Synopsis
run-one COMMAND [ARGS] run-this-one COMMAND [ARGS] run-one-constantly COMMAND [ARGS] keep-one-running COMMAND [ARGS] run-one-until-success COMMAND [ARGS] run-one-until-failure COMMAND [ARGS] Description
run-one is a wrapper script that runs no more than one unique instance of some command with a unique set of arguments. This is often useful with cronjobs, when you want no more than one copy running at a time. run-this-one is exactly like run-one, except that it will use pgrep(1) and kill(1) to find and kill any running processes owned by the user and matching the target commands and arguments. Note that run-this-one will block while trying to kill matching processes, until all matching processes are dead. run-one-constantly operates exactly like run-one except that it respawns "COMMAND [ARGS]" any time COMMAND exits (zero or non-zero). keep-one-running is an alias for run-one-constantly. run-one-until-success operates exactly like run-one-constantly except that it respawns "COMMAND [ARGS]" until COMMAND exits successfully (ie, exits zero). run-one-until-failure operates exactly like run-one-constantly except that it respawns "COMMAND [ARGS]" until COMMAND exits with failure (ie, exits non-zero). Example
In one shell: $ run-one rsync -azP $HOME [email protected]:/srv/backup foouser/ foouser/.bash_history 40298 100% 37.13MB/s 0:00:00 (xfer#1, to-check=3509/3516) foouser/.viminfo 20352 100% 98.39kB/s 0:00:00 (xfer#3, to-check=3478/3516) ... sent 746228 bytes received 413059 bytes 36802.76 bytes/sec total size is 3732890955 speedup is 3219.99 In another shell, while the first is still running: $ run-one rsync -azP $HOME [email protected]:/srv/backup $ echo $? 1 Another example... In one shell: $ run-one top In another shell: $ run-one top $ echo $? 1 $ run-this-one top top - 17:15:36 up 1:43, 3 users, load average: 1.05, 1.04, 1.00 Tasks: 170 total, 1 running, 169 sleeping, 0 stopped, 0 zombie ... And note that the process in the first shell was killed. You might want to keep one ssh connection up and running all the time, with: $ run-one-constantly ssh -N -C -L 3128:localhost:3128 -L 7778:localhost:7778 example.com & See Also
flock(1), kill(1), pgrep(1)
Author
This manpage and the utility was written by Dustin Kirkland <[email protected]> for Ubuntu systems (but may be used by others). Permission is granted to copy, distribute and/or modify this document under the terms of the GNU General Public License, Version 3 published by the Free Software Foundation. On Debian systems, the complete text of the GNU General Public License can be found in /usr/share/common-licenses/GPL, or on the web at http://www.gnu.org/licenses/gpl.txt.