Shell Programming and Scripting

... i'm no expert but ...

if you're running the script or program on the command line by yourself --- it's running interactively

if the script is regularly running at specific times (i.e., at 1 PM every day) without your intervention or anybody else's --- it's most likely being run by cron (see "man cron")

What he meant was he wants his script to determine if it running via cron so that it can take different actions. For example an interactive script might give a progress report and request permission to proceed to phase 2. An interactive script might just send errors to fd 2 while a cron run script might:
mv /var/log/somescript/errors /var/log/somescript/errors.old
exec 2> /var/log/somescript/errors
or something like that.

now i get it ...

have the script check for $TERM --- if set, the script is most likely running interactively ... if not, the script is most likely running through cron ...

Code:

#! /bin/ksh

if [ $TERM ]
then
    echo "I'm running interactively."
else
    echo "I'm running through cron" | mailx -s "cron test" user@domain.com
fi

exit 0

Code:

#!/bin/ksh
if [ -t 0 ] ; then
   echo "I am interactive"
else
   echo "I have no controlling terminal - cronned?"
fi;

That was what I said in #3.

... my apologies ... my wrong interpretation of the question didn't help my understanding of what people have posted ... going back through the posts now ... pixelbeat posted similar code but i missed that too ... seems i need new glasses or at least a brain that works ...

Hi,

Am new and got registered only for this one thread......
Well got the same prob. but i need to differentiate if my script was invoked by rc script or by cron.....i used this but prob is that the parent of my perl script is shown as shell (bash) and not cron and that is not what i want.....how do i get around this??????

$cronpid=`ps -ef|grep cron| awk '{if(NR==1) print \$2;}'`;
$parentpid=`ps -ef | grep action.pl |awk '{if(NR == 1) print \$3; }'`;
$printst=`ps -ef| grep action.pl`;
print "Output of ps is\n$printst\n ";
print "************Cron pid is $cronpid and parentpid is $parentpid\n**************";
$printst1=`ps -ef | grep $parentpid`;
print "My parent is\n $printst\n";
if($cronpid == $parentpid){
print "This process was invoked by cron...it cannot reboot machine";
$rebootnow=2;
}
else{ print "Rebooting.....";
}

Output shown is---------------------
Output of ps is
pooja 10890 8350 0 16:43 pts/0 00:00:00 /usr/bin/perl ./action.pl
pooja 10915 10890 0 16:43 pts/0 00:00:00 sh -c ps -ef| grep action.pl

************Cron pid is 7877
and parentpid is 8350

**************My parent is
pooja 10890 8350 0 16:43 pts/0 00:00:00 /usr/bin/perl ./action.pl
pooja 10915 10890 0 16:43 pts/0 00:00:00 sh -c ps -ef| grep action.pl