in reply to Re^2: Script hangs when executing command over ssh
in thread Script hangs when executing command over ssh

If there's a way to work with the buffer, hopefully a more Unix/Linux-oriented Monk will come along with a suggestion. However, I don't think you understood my point about getting rid of the piping.

Try removing the 1>&2from your command, and see if the problem goes away.

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Re^4: Script hangs when executing command over ssh
by eg2014 (Initiate) on Jun 18, 2015 at 18:28 UTC

    I understand your point regarding the output redirection. Removing 1>&2 from the command does get rid of the problem in this specific example.

    However the actual program is being run like  $ssh->cmd('/bin/a'); and it writes some output to STDERR, and unfortunately I do not have any control over that. Thank you

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[d/l]

      Your answer still leaves me believing you're not getting my point.

      • Yes, the program writes to STDERR.
      • Yes, you cannot control this.
      • We suspect STDERRhas special handling issues.
      • You are messing with STDERRwhen you re-pipe it using 1>&2.
      • Messing with it might be the source of the hang.

      Thus, I'm hoping that removing the 1>&2from your script might prevent the hanging under all cases.

      But it might not. Won't know until you try it against all known cases that currently cause it to hang.

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[d/l]
[select]
        Thank you again for your help. Points 1-3 are correct but 3-4 are not. The original program writes the data to STDERR and hangs. I have demonstrated the behavior using the script above for simplicity - but in fact the behavior is the same using a program which writes to STDERR and the above example which uses redirection to write to STDERR.
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