What is the cleanest way to ssh and run multiple commands in Bash?
I already have an ssh agent set up, and I can run commands on an external server in Bash script doing stuff like:
ssh blah_server "ls; pwd;"
Now, what I'd really like to do is run a lot of long commands on an external server. Enclosing all of these in between quotation marks would be quite ugly, and I'd really rather avoid ssh'ing multiple times just to avoid this.
So, is there a way I can do this in one go enclosed in parentheses or something? I'm looking for something along the lines of:
ssh blah_server (
ls some_folder;
./someaction.sh;
pwd;
)
Basically, I'll be happy with any solution as long as it's clean.
Edit
To clarify, I'm talking about this being part of a larger bash script. Other people might need to deal with the script down the line, so I'd like to keep it clean. I don't want to have a bash script with one line that looks like:
ssh blah_server "ls some_folder; ./someaction.sh 'some params'; pwd; ./some_other_action 'other params';"
because it is extremely ugly and difficult to read.
How about a Bash Here Document:
ssh otherhost << EOF
ls some_folder;
./someaction.sh 'some params'
pwd
./some_other_action 'other params'
EOF
To avoid the problems mentioned by @Globalz in the comments, you may be able to (depending what you're doing on the remote site) get away with replacing the first line with
ssh otherhost /bin/bash << EOF
Note that you can do variable substitution in the Here document, but you may have to deal with quoting issues. For instance, if you quote the "limit string" (ie. EOF in the above), then you can't do variable substitutions. But without quoting the limit string, variables are substituted. For example, if you have defined $NAME above in your shell script, you could do
ssh otherhost /bin/bash << EOF
touch "/tmp/${NAME}"
EOF
and it would create a file on the destination otherhost with the name of whatever you'd assigned to $NAME . Other rules about shell script quoting also apply, but are too complicated to go into here.
Edit your script locally, then pipe it into ssh, eg
cat commands-to-execute-remotely.sh | ssh blah_server
where commands-to-execute-remotely.sh looks like your list above:
ls some_folder
./someaction.sh
pwd;
I see two ways:
First you make a control socket like this:
ssh -oControlMaster=yes -oControlPath=~/.ssh/ssh-%r-%h-%p <yourip>
and run your commands
ssh -oControlMaster=no -oControlPath=~/.ssh/ssh-%r-%h-%p <yourip> -t <yourcommand>
This way you can write an ssh command without actually reconnecting to the server.
The second would be to dynamically generate the script, scp ing it and running.