keep-one-running

run-one(1)                          run-one                         run-one(1)

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 $USER@example.com:/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 $USER@example.com:/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:local-
       host:7778 example.com &

SEE ALSO
       flock(1), kill(1), pgrep(1)

AUTHOR
       This  manpage  and  the  utility  was written by Dustin Kirkland <kirk-
       land@ubuntu.com> for Ubuntu systems (but may be used by others).   Per-
       mission  is granted to copy, distribute and/or modify this document un-
       der 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.

run-one                           9 Jan 2011                        run-one(1)