I'm struggling with trying to identify a failure in a set of piped commands run on a remote host via ssh. I use perl to build and run the command line as below

ssh $TARGET_HOST "sudo find $TARGET_DIR -name \'$TARGET_FILE\' | sudo 
+cpio --create --format ustar" | bzip2 -9 -c
[download]

Initially I just redirected the output to a file, which is fine if both the $TARGET_DIR and $TARGET_FILE exists. However, if one or both do not exist, then I still get a file created, but it's empty.
Things I've tried:
With $ret=system($cmd); and testing the the value of $ret:

Pre-fixing the cmd with set -o pipefail &&.

Adding set -o pipefail to the command run by ssh.

Adding set -o pipefail to the command run by sudo.

Doing the bzip2 locally.
With @results = `$cmd`, and testing the value of $?:

Adding ; echo \${PIPESTATUS\@}; to the end of $cmd, within the string passed to ssh.

Adding ; echo \${PIPESTATUS\@}; to the end of $cmd, after the string passed to ssh.
Using the @results approach, I only get one entry, so I suspect that the backtick method only sees one stream?

Any ideas on how I can detect the remote pipeline failure?

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In reply to Re^3: best practices for checking system return values for piped commands? by Anonymous Monk
in thread best practices for checking system return values for piped commands? by markjugg

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