/usr/bin/chronic is in moreutils 0.57-1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 | #!/usr/bin/perl
=head1 NAME
chronic - runs a command quietly unless it fails
=head1 SYNOPSIS
chronic COMMAND...
=head1 DESCRIPTION
chronic runs a command, and arranges for its standard out and standard
error to only be displayed if the command fails (exits nonzero or crashes).
If the command succeeds, any extraneous output will be hidden.
A common use for chronic is for running a cron job. Rather than
trying to keep the command quiet, and having to deal with mails containing
accidental output when it succeeds, and not verbose enough output when it
fails, you can just run it verbosely always, and use chronic to hide
the successful output.
0 1 * * * chronic backup # instead of backup >/dev/null 2>&1
=head1 AUTHOR
Copyright 2010 by Joey Hess <id@joeyh.name>
Original concept and "chronic" name by Chuck Houpt.
Licensed under the GNU GPL version 2 or higher.
=cut
use warnings;
use strict;
use IPC::Run qw( start pump finish timeout );
if (! @ARGV) {
die "usage: chronic COMMAND...\n";
}
my ($out, $err);
my $h = IPC::Run::start \@ARGV, \*STDIN, \$out, \$err;
$h->finish;
my $ret=$h->full_result;
if ($ret >> 8) { # child failed
showout();
exit ($ret >> 8);
}
elsif ($ret != 0) { # child killed by signal
showout();
exit 1;
}
else {
exit 0;
}
sub showout {
print STDOUT $out;
print STDERR $err;
}
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