[SOLVED] replace argument with an IP address

Issue

I have a list of about 50 systems with unique ip addresses that i need to regularly ssh into. I know these systems by a four digit alphanumeric number, but am constantly having to look up the ip addresses whenever I ssh into them. I would like to create a bash script that contains a list of all of the IP addresses for each machine, and i can type:

ssh_script aa11

and it executes:

ssh 111.222.333.444

Follow up question: some of the systems require a port # but i would still like to just type ssh_script bb22 and it does

ssh 333.444.555.666 -p 4444

Is this possible?

Solution

This should be easy as such.

#!/bin/sh
port=22
case $1 in
 aa11) host=111.222.333.444;;
 bb22) host=333.444.555.666
    port=4444;;
 *) echo "$0: host $1 unknown" >&2
    exit 2;;
esac
exec ssh -p "$port" "$host"

(This script uses no Bash features, so I put #!/bin/sh. It should work with Bash as well, of course.)

But probably a better solution is to configure this in your ~/.ssh/config instead; then it will also work transparently for scp and programs which invoke ssh internally, like for example git.

Host aa11
  Hostname 111.222.333.444

Host bb22
  Hostname 333.444.555.666
  Port 4444

See the ssh_config manual page for details about this file.

You can combine the two;

#!/bin/sh

test -e ~/.ssh/config_too || cat <<\: >~/.ssh/config_too
Host aa11
  Hostname 111.222.333.444

Host bb22
  Hostname 333.444.555.666
  Port 4444
:
exec ssh -F ~/.ssh/config_too "$@"

(Not all sh instances necessarily support ~ even though it's now mandated by POSIX; maybe switch to "$HOME"/.ssh/config_too if you have an oldish sh on some systems.)

Answered By - tripleee