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    <p>You can daemonize any executable in Unix by using nohup and the &amp; operator:</p> <pre><code>nohup yourScript.sh script args&amp; </code></pre> <p>The nohup command allows you to shut down your shell session without it killing your script, while the &amp; places your script in the background so you get a shell prompt to continue your session. The only minor problem with this is standard out and standard error both get sent to ./nohup.out, so if you start several scripts in this manor their output will be intertwined. A better command would be:</p> <pre><code>nohup yourScript.sh script args &gt;script.out 2&gt;script.error&amp; </code></pre> <p>This will send standard out to the file of your choice and standard error to a different file of your choice. If you want to use just one file for both standard out and standard error you can us this:</p> <pre><code>nohup yourScript.sh script args &gt;script.out 2&gt;&amp;1 &amp; </code></pre> <p>The 2>&amp;1 tells the shell to redirect standard error (file descriptor 2) to the same file as standard out (file descriptor 1).</p> <p>To run a command only once and restart it if it dies you can use this script:</p> <pre><code>#!/bin/bash if [[ $# &lt; 1 ]]; then echo "Name of pid file not given." exit fi # Get the pid file's name. PIDFILE=$1 shift if [[ $# &lt; 1 ]]; then echo "No command given." exit fi echo "Checking pid in file $PIDFILE." #Check to see if process running. PID=$(cat $PIDFILE 2&gt;/dev/null) if [[ $? = 0 ]]; then ps -p $PID &gt;/dev/null 2&gt;&amp;1 if [[ $? = 0 ]]; then echo "Command $1 already running." exit fi fi # Write our pid to file. echo $$ &gt;$PIDFILE # Get command. COMMAND=$1 shift # Run command until we're killed. while true; do $COMMAND "$@" sleep 10 # if command dies immediately, don't go into un-ctrl-c-able loop done </code></pre> <p>The first argument is the name of the pid file to use. The second argument is the command. And all other arguments are the command's arguments.</p> <p>If you name this script restart.sh this is how you would call it:</p> <pre><code>nohup restart.sh pidFileName yourScript.sh script args &gt;script.out 2&gt;&amp;1 &amp; </code></pre>
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    1. POHow do I daemonize an arbitrary script in unix?
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    1. USKevin
    1. USRobert Menteer
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    1. POHow do I daemonize an arbitrary script in unix?
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    1. COAwesome; thank you. I wonder if it should also have an option for a delay in restarting. Or maybe better to just use it in conjunction with this: http://stackoverflow.com/questions/555116/repeat-a-unix-command-every-x-seconds-forever
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    2. COThis handles only SIGHUP, there are other (normally) fatal signals that should be handled.
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      1. USTim Post
    3. COAnother way to improve this script is probably to have it come up with a good location to place the $PIDFILE on its own rather than requiring it to be specified as an arg. It doesn't even clean up after itself! (which should be straightforward with a `trap EXIT`)
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      1. USSteven Lu
 

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