LinuxQuestions.org - lsof output not redirecting in a cronjob

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lsof output not redirecting in a cronjob

When I run this command as root, I get the correct output of all open files opened by by the process 5018

lsof -p 5018 > lsof_output.txt

However, when I put this in a cron job

56 13 * * * lsof -p 5018 2>&1 > /root/lsof_output.txt

no output is written to lsof_output.txt

I confirmed that the job runs, by actually deleting the file before the scheduled time. A new empty file is created with no content. The process 5018 is active at the time the cron job runs.

What am I missing?

Thanks in advance.

Try using the fully-qualified path to lsof(8). If you're not sure where it is, find out with:

Code:

# whereis lsof

Thank you....that helped

Quote:

Originally Posted by threezerous (Post 4483722)

What am I missing?

...I'd say you're missing more than just the cron PATH inclusion:
- when listing things always look for switches like "-n" as they may speed up processing by not translating. For lsof it's "-Pwln".
- using "-p $PID" is not extensible. Could pick up the actual PID with for example something like 'pgrep' ('man pgrep').
- root is no ordinary user and as such you shouldn't use it for write ops: use /tmp (or /dev/shm) for scratch files, /var/log for log files or 'logger' to pipe output into say syslog. If you're writing temporary files try using 'mktemp'.

Put together:

Code:

#!/bin/bash --

umask 0027; TEMPFILE=`mktemp /dev/shm/lsof.XXXXXXXXXXXX` && {

 pgrep sendmail 2>/dev/null|xargs -iP /usr/sbin/lsof -Pwlnp 'P' > "${TEMPFILE:/tmp/$$}" 2>&1

 [ -s "${TEMPFILE:/tmp/$$}" ] && install -o root -g root -m 0640 "${TEMPFILE:/tmp/$$}" "/var/log/lsof_$(/bin/date +'%Y%m%d').log"

 rm -f "${TEMPFILE:/tmp/$$}"

}; exit 0

Code:

function help() { echo "Bash scripting guides:

http://www.tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html 

http://www.tldp.org/LDP/Bash-Beginners-Guide/html/index.html 

http://www.gnu.org/software/bash/manual/html_node/index.html

http://www.grymoire.com/Unix/Sh.html

http://www.tldp.org/LDP/abs/html/ 

http://wooledge.org/mywiki/BashFAQ?action=show&redirect=BashFaq 

http://wooledge.org/mywiki/BashPitfalls"; }