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Full Discussion: Error redirection question
Top Forums Shell Programming and Scripting Error redirection question Post 302555796 by Corona688 on Thursday 15th of September 2011 03:48:56 PM
Old 09-15-2011
Standard error doesn't pass through pipes. It goes directly to the terminal. So redirecting the last command only redirects errors the last program prints.

Code:
command 2> errlog | command2 | command3

It's extremely wasteful to run awk to process single lines. Might be better to do this:

Code:
[ -r test.dat ] && export LINE_COUNT=`wc -l < test.dat` || echo "Can't read test.dat" >&2

Faster since it uses less processes, and the error messages can be whatever you'd like.
This User Gave Thanks to Corona688 For This Post:
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LEARN ABOUT DEBIAN

arp2ethers

ARP2ETHERS(8)						      System Manager's Manual						     ARP2ETHERS(8)

NAME

       arp2ethers - convert arpwatch address database to ethers file format

SYNOPSIS

       arp2ethers [ arp.dat file ]

DESCRIPTION

       arp2ethers  converts  the file /var/lib/arpwatch/arp.dat (or the file specified on the command line) into ethers(5) format on stdout.  Usu-
       ally arp.dat is an ethernet/ip database file generated by arpwatch(8).  The arpwatch daemon in Debian will create different arp.dat depend-
       ing on its configuration. All of them will be available at /var/lib/arpwatch/.

FILES

       /var/lib/arpwatch - default directory for arp.dat
       arp.dat - ethernet/ip address database

SEE ALSO

       arpwatch(8), ethers(5), rarp(8), arp(8),

BUGS

       Please send bug reports to arpwatch@ee.lbl.gov.

AUTHORS

       Original  version  by  Craig Leres of the Lawrence Berkeley National Laboratory Network Research Group, University of California, Berkeley,
       CA.

       Modified for the Debian Project by Peter Kelemen, with additions from Erik Warmelink.

       The current version is available via anonymous ftp:

	      ftp://ftp.ee.lbl.gov/arpwatch.tar.gz

       This manual page was contributed by Hugo Graumann.

																     ARP2ETHERS(8)
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