This is the command keep-one-running that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator
PROGRAM:
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:localhost:7778 example.com
&
Use keep-one-running online using onworks.net services