What is the cleanest way to ssh and run multiple commands in Bash?

问题:

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.

回答1:

How about a Bash Here Document:

ssh otherhost 

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 

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 

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.

回答2:

Edit your script locally, then pipe it into ssh, e.g.

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; 

回答3:

I see two ways:

First you make a control socket like this:

 ssh -oControlMaster=yes -oControlPath=~/.ssh/ssh-%r-%h-%p 

and run your commands

 ssh -oControlMaster=no -oControlPath=~/.ssh/ssh-%r-%h-%p  -t 

This way you can write an ssh command without actually reconnecting to the server.

The second would be to dynamically generate the script, scping it and running.

回答4:

To match your sample code, you can wrap your commands inside single or double qoutes. For example

ssh blah_server "   ls   pwd " 

回答5:

This can also be done as follows. Put your commands in a script, let's name it commands-inc.sh

#!/bin/bash ls some_folder ./someaction.sh pwd 

Save the file

Now run it on the remote server.

ssh user@remote 'bash -s' 

Never failed for me.

回答6:

Put all the commands on to a script and it can be run like

ssh @ "bash -s" <.>

回答7:

SSH and Run Multiple Commands in Bash.

Separate commands with semicolons within a string, passed to echo, all piped into the ssh command. For example:

echo "df -k;uname -a" | ssh 192.168.79.134  Pseudo-terminal will not be allocated because stdin is not a terminal. Filesystem     1K-blocks    Used Available Use% Mounted on /dev/sda2       18274628 2546476  14799848  15% / tmpfs             183620      72    183548   1% /dev/shm /dev/sda1         297485   39074    243051  14% /boot Linux newserv 2.6.32-431.el6.x86_64 #1 SMP Sun Nov 10 22:19:54 EST 2013 x86_64 x86_64 x86_64 GNU/Linux 

回答8:

This works well for creating scripts, as you do not have to include other files:

#!/bin/bash ssh @ "bash -s" 

回答9:

The easiest way to configure your system to use single ssh sessions by default with multiplexing.

This can be done by creating a folder for the sockets:

mkdir ~/.ssh/controlmasters 

And then adding the following to your .ssh configuration:

Host *     ControlMaster auto     ControlPath ~/.ssh/controlmasters/%r@%h:%p.socket     ControlMaster auto     ControlPersist 10m 

Now, you do not need to modify any of your code. This allows multiple calls to ssh and scp without creating multiple sessions, which is useful when there needs to be more interaction between your local and remote machines.

Thanks to @terminus's answer, http://www.cyberciti.biz/faq/linux-unix-osx-bsd-ssh-multiplexing-to-speed-up-ssh-connections/ and https://en.wikibooks.org/wiki/OpenSSH/Cookbook/Multiplexing.

回答10:

For anyone stumbling over here like me - I had success with escaping the semicolon and the newline:

First step: the semicolon. This way, we do not break the ssh command:

ssh  echo test\;ls                     ^ backslash! 

Listed the remote hosts /home directory (logged in as root), whereas

ssh  echo test;ls                     ^ NO backslash 

listed the current working directory.

Next step: breaking up the line:

                      v another backslash! ssh  echo test\;\ ls 

This again listed the remote working directory - improved formatting:

ssh \   echo test\;\   ls 

If really nicer than here document or quotes around broken lines - well, not me to decide...

(Using bash, Ubuntu 14.04 LTS.)

回答11:

The posted answers using multiline strings and multiple bash scripts did not work for me.

• Long multiline strings are hard to maintain.
• Separate bash scripts do not maintain local variables.

Here is a functional way to ssh and run multiple commands while keeping local context.

LOCAL_VARIABLE=test  run_remote() {     echo "$LOCAL_VARIABLE"     ls some_folder;      ./someaction.sh 'some params'     ./some_other_action 'other params' }  ssh otherhost "$(set); run_remote" 

文章来源: What is the cleanest way to ssh and run multiple commands in Bash?