Reading output of command in bash and check if failed.

[carelburger]

Hi,

I have a bash script that I wrote and it calls flexget which then give an output like this:



2011-02-26 15:11 INFO feed MyTracker Produced 1 entries.
2011-02-26 15:11 INFO feed MyTracker Accepted: 1 (Rejected: 0 Undecided: 0 Failed: 0)
2011-02-26 15:11 INFO download MyTracker Downloading: Test
2011-02-26 15:11 INFO modify_trackers MyTracker Added http://test.net/announce.php?passkey=714c390d9916a735964c0a7ba7b6a a3d tracker to Test
2011-02-26 15:11 INFO deluge MyTracker Connecting to daemon at localhost:58846..
2011-02-26 15:11 INFO deluge MyTracker Connected to daemon at localhost:58846..
2011-02-26 15:11 INFO deluge MyTracker Test successfully added to deluge.
2011-02-26 15:11 INFO deluge MyTracker Connection lost to daemon at localhost:58846 reason: Connection was closed cleanly.

Ok so there it was successfull, but if not it would say failed.

The command looks like this:


flexget --feed=MyTracker --inject "$filename" "$HTTPDownloadLocation$filenameWithoutSpaces$Torren tExtension" --cli-config "path=$directory"

How can I pipe this output from flexget and look at the output and determine if it was successfull or a failure. I need to run different commands with a if statement depending on the success of the command.

[johnl]

Hi,

Most programs will return 0 on success or non-zero on failure. This is stored in the special variable $?

You can check like this:



flexget --feed=MyTracker --inject "$filename" "$HTTPDownloadLocation$filenameWithoutSpaces$Torren tExtension" --cli-config "path=$directory"
RESULT=$?

if [ $RESULT -ne 0 ]; then
echo "flexget failed with code $RESULT"
fi


alternatively, flexget may not do this (some programs don't). In this case you can use grep - q and look for a certain string in the output. For example, if when the command fails it prints "failure" to standard out, you can do something like this:



flexget --feed=MyTracker --inject "$filename" "$HTTPDownloadLocation$filenameWithoutSpaces$Torren tExtension" --cli-config "path=$directory"| grep -q "failure"

RESULT=$? # grep will return 0 if it finds 'failure', non-zero if it didn't

if [ $RESULT -eq 0 ]; then
echo "flexget failed with code $RESULT"
fi


hope this helps.