Administering hundreds of systems can be tedious. Sometimes scripting repetitive tasks, or replicating tasks across many servers is necessary.
Over time, I’ve jotted down several quick useful notes regarding using various linux/unix commands. I’ve found them very useful when navigating and performing various tasks. I decided to share them with you, so hopefully you will find them a useful reference at the very least!
To find files within a time range and add up the total size of all those files :
find /opt/uploads -mtime -365 -printf "%sn"|awk '{sum+=$0}END{print sum}'To watch a command’s progress :
watch -n1 'du -h -c --max-depth=1'
Transfer a file / folders, compress it midstrem over the network, uncompress the file on the recieving end:
ssh -l root 00.00.000.000 '(cd /opt/uploads/ && tar -czf - . -C /opt/uploads)' | tar -xzf -
Below will return any XYZ PID that is older than 10 hours.
ps -ef | grep XYZ | awk '{ print $7 ":" $2 }' | awk 'BEGIN { FS =":" }; {if ($1 > 10) print $4}'Check web logs on www server for specific ip address access:
grep "ip_address" [a-h]*/logs/*access*4 <-- check a-h websites grep "ip_address" [A-Z,0-9]*/logs/*access*4 <-- check A-Z, 0-9 websites
Those are just a few of the useful commands that can be applied to many different functions. I particularly like sending files across the network and compressing them mid stream :)
The above kind of administration is made even easier when you employ ssh key based authentication -- your commands can be scripted to execute across many servers in one sitting (just be careful) ;)
