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redirecting to /dev/null

305 votes
6 answers
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I'm reading an example bash shell script: #!/bin/bash # This script makes a backup of my home directory. cd /home # This creates the archive tar cf /var/tmp/home_franky.tar franky > /dev/null 2>&1 # First remove the old bzip2 file. Redirect errors because this generates some if the archive # does not exist. Then create a new compressed file. rm /var/tmp/home_franky.tar.bz2 2> /dev/null bzip2 /var/tmp/home_franky.tar # Copy the file to another host - we have ssh keys for making this work without intervention. scp /var/tmp/home_franky.tar.bz2 bordeaux:/opt/backup/franky > /dev/null 2>&1 # Create a timestamp in a logfile. date >> /home/franky/log/home_backup.log echo backup succeeded >> /home/franky/log/home_backup.log I'm trying to understand the use of /dev/null 2>&1 here. At first, I thought this script uses /dev/null in order to gracefully ignore errors, without causing the script to crash (kind of like try catch exception handling in programming languages). Because I don't see how using tar to compress a directory into a tar file could possibly cause any type of errors.
Asked by JohnMerlino (6491 rep)
Mar 14, 2014, 04:20 AM
Last activity: Apr 2, 2022, 05:25 PM