Originally published January 7, 2018 @ 2:50 pm
Let’s say you run the same command on two remote servers and you want to compare the output. Here’s a quick example:
diff <(ssh -qtT server01 "sudo su - root -c 'fdisk -l 2>/dev/null | grep ^Disk'") <(ssh -qtT server02 "sudo su - root -c 'fdisk -l 2>/dev/null | grep ^Disk'")
I suggest using “vimdiff” for a more easy-to-read layout:
yum -y install vim
vimdiff <(ssh -qtT server01 "sudo su - root -c 'fdisk -l 2>/dev/null | grep ^Disk'") <(ssh -qtT server02 "sudo su - root -c 'fdisk -l 2>/dev/null | grep ^Disk'")
Here’s another vimdiff example that ignores white spaces and uses a small script to auto-close in three seconds. The /tmp/vimscript looks like this:
:sleep 3 :qa!
And the whole command is this:
vimdiff -c 'set diffopt+=iwhite' -s /tmp/vimscript <(ssh -qtT server2 "sudo su - root -c 'cat /etc/hosts'") <(ssh -qtT server1 "sudo su - root -c 'cat /etc/hosts'")
This may be useful if you need to do a quick visual comparison of multiple files. For example, find *.conf in /etc on server1 and compare them to equivalent files on server2:
for i in $(ssh -qtT server1 "sudo su - root -c 'find /etc -maxdepth 2 -type f -name "*\.conf"'" -mtime -7)
do
vimdiff -c 'set diffopt+=iwhite' -s /tmp/vimscript <(ssh -qtT server1 "sudo su - root -c 'cat ${i}'") <(ssh -qtT server2 "sudo su - root -c 'cat ${i}'")
done
Experienced Unix/Linux System Administrator with 20-year background in Systems Analysis, Problem Resolution and Engineering Application Support in a large distributed Unix and Windows server environment. Strong problem determination skills. Good knowledge of networking, remote diagnostic techniques, firewalls and network security. Extensive experience with engineering application and database servers, high-availability systems, high-performance computing clusters, and process automation.
