Check file modification on two servers

Question

If I have a file namely /etc/file.cfg on server A and server B. How can we check whether the file on Server A is newer than file on server B ?

If it was on a local machine then we would have used file1 -nt file2.

Answer 1

If you have ssh access you can try something like below. Note that there is no error checking, for instance if remote files do not exist this would fail.

REMOTE_TIME_1=$(ssh user@remote "ls -l --time-style=+%s remote_file  | cut -d ' ' -f 6")
REMOTE_TIME_2=$(ssh user@remote "ls -l --time-style=+%s remote_file  | cut -d ' ' -f 6")
if (( REMOTE_TIME_1 > REMOTE_TIME_2 )); 
then 
    echo first file is older
else
    echo second file is older
fi

Note that if you do not want to enter password everytime you can use the ssh-copy-id command to copy your public key to the remote server's authorized_keys files.