Redirections

• I said I thought this code had been written by an ex-C-programmer

• Why not an ex-shell programmer?

  • Well, mainly because shell programmers never declare anything

• But also:

system("unzip -v '$incoming_dir/$file' 2>&1 >/dev/null");

• Here the intent was to discard standard output and standard error

• But it only discards stdout

• 2>&1 means "send stderr to wherever stdout is going"

• >/dev/null means "send stdout to /dev/null"

• The order is important here

• It should have been:

system("unzip -v '$incoming_dir/$file' >/dev/null 2>&1");

• That's not a red flag; just a bug

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Copyright © 2006 M. J. Dominus