Bash script for moving and renaming application log files on Linux - linux

Question

I'm relatively new to coding on linux.
I have the below script for moving my ERP log file.
!/bin/bash #Andrew O. MBX 2015-09-03
#HansaWorld Script to periodically move the log file
_now=$(date +"%m_%d_%Y")
mv /u/OML_Server_72/hansa.log /u/HansaLogs/hansa_$now.log
The code runs but does not rename the log file to the date it has been moved.
I would also like to check when the file exceeds the 90M size so it moves it automatically at the end of every day. a cron job of some kind.
Help Please
After editing this is my new code.
#!/bin/bash
#Andrew O. MBX 2015-09-03
#HansaWorld Script to periodically move the log file
now=$(date +"%m_%d_%Y")
mv /u/OML_Server_72/hansa.log /u/HansaLogs/hansa$now.log
I wish to add code to check if hansa.log file is over 90M then move it. If it is not then leave it as it is.
cd /u find. -name '*hansa.log*' -size +90000k -exec mv '{}' /u/HansaLogs\;

Answer 1

In addition to the other comments, there are a few other things to consider. tgo's logrotate suggestion is a good one. In Linux, if you are every stuck on the use of a utility, etc.. the man files (while a bit cryptic at first), provide concise usage information. To see the logs available for a given utility, use man -k name (some distributions provide this selection capability by default alias) e.g.:
$ man -k logrotate
logrotate (8) - rotates, compresses, and mails system logs
logrotate.conf (5) - rotates, compresses, and mails system logs
Then if you want the logrotate page:
$ man 8 logrotate
or the conf page
$ man 5 logrotate.conf
There are several things you may want to change/consider regarding your script. First, while there is nothing wrong with a variable now, you may run into confusion with the date command's builtin use of now. There is no conflict, but it would look strange to write now=$(date -d "now + 24 hours" "+%F %T"). (recommend a name like tstamp, short for timestamp instead).
For maintainability, readability, etc... you may consider assiging your path components to variables that will help with readability later on. (example below).
Finally, before moving, copying, deleting, etc... it is always a good idea to validate that the target file exists and to provide an error message if something is out of whack. A rewrite could be:
#!/bin/bash
#Andrew O. MBX 2015-09-03
#HansaWorld Script to periodically move the log file
tstamp=$(date +"%m_%d_%Y")
logdir="/u/HansaLogs"
logname="/u/OML_Server_72/hansa.log"
if [ -f "$logname" ]; then
mv "$logname" "$logdir/hansa_${tstamp}.log"
else
printf "error: file not found '%s'.\n" "$logname" >&2
exit 1
fi
Note: the >&2 simply redirects the output of printf to stderr rather than stdout.
As for the find command, there is no need to cd and find ., the find command takes the path as its first argument. Additionally, the --size option has builtin support for Megabytes M. A rewrite here could look like:
find /u -name "*hansa.log*" -size +90M -exec mv '{}' /u/HansaLogs \;
All in all, it looks like you will pick up shell programming without any problem. Just develop good habits early, they will save you a lot of grief later.

Answer 2

Hi Guys Thanx for the help. So far I have come up with this code. I am stuck at creating a cron job to run this periodically say after every 22hrs
#!/bin/bash
#Andrew O. MBX 2015-09-03
#HansaWorld Script to Check if log file exists before moving:
tstamp=$(date +"%m_%d_%Y")
logdir="/u/HansaLogs"
logname="/u/OML_Server_72/hansa.log"
minimumsize=90000
actualsize=$(wc -c <"$logname")
if [ $actualsize -ge $minimumsize ]; then
mv "$logname" "$logdir/hansa_${tstamp}.log"
else
echo size is under $minimumsize bytes
exit 1
fi