how to get /log fS usage in two remote servers

First of all, you need to remove the requirement to use a password to log into your servers. Use public key based logins instead. Once you've don that, you'll need something like:

$ for host in "server1" "server2" ; do echo $host; ssh $host df --output="ipcent" /tmp | tail -n1 | tr -d " "; done | pr --columns=2  --length=2 | mail [email protected]

should work.

The line loops through both server1 and server2 and runs the command:

echo $host; ssh $host df --output="ipcent" /tmp

on each server in turn. The output of this is simply the server name ($host) followed by the percentage use of the drive containing /tmp, but it has a header, so that is removed by piping it to:

tail -n1

which returns the last line (the percentage). Unfortunately, that is surrounded by whitespace, so that is removed by piping it to:

tr -d " "

At this point, both servers would have been ssh'd, but the output would be something like:

server1
75%
server2
50%

so it is piped into:

pr --columns=2 --length=2

in order to rotate it to the format you requested:

server1     server2
75%         50%

Finally, this is piped into:

mail [email protected]

to email it to bloggs.