CODEWITHSUNDEEP
bashemail
jrodder
jrodder

Reputation: 23

BASH tail logfile and send mail on matched condition

Completely clueless with Bash, but trying to learn to accomplish this single task.

I need a script that can tail the last 50 lines of a logfile, looking for the string "ERROR", and send an email if that condition is true.

I can do bits and pieces manually, but am not able to build something that works completely to stick in a cron. Sendmail works by itself.

tail -n 50 /var/log/unifi-video/recording.log | grep ERROR

works to at least output that. Ideally I'd like an email only if ERROR is found in the last 50 lines, else no action needs to be taken. If anyone can assist with the if/else statement to make this happen, it would be greatly appreciated.

Upvotes: 2

Views: 5714

Answers (2)

chepner
chepner

Reputation: 532043

grep exits with status 0 if a match is found, 1 if not, so something like

 tail -n 50 /var/log/unifi-video/recording.log | grep -q ERROR && <sendmail command here>

would do what you want. (The -q option suppresses any output, because you don't care what line actually matched, just that a match was found.)

Upvotes: 0

JNevill
JNevill

Reputation: 50218

If you are looking to do this in a one liner you could use something like:

[ $(tail -n 50 /var/log/unifi-video/recording.log | grep ERROR | wc -l) -gt 0 ] && yourmailcommand

This just pipes the output of your grep to wc -l which returns how many lines are returned from grep. If that count is greater than 0 then it will execute that bit after the double ampersands. If you want to include an else in the event that no ERROR lines are found you could:

[ $(tail -n 50 /var/log/unifi-video/recording.log | grep ERROR | wc -l) -gt 0 ] && yourmailcommand || dosomethingelseinstead

Upvotes: 1

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