CODEWITHSUNDEEP
linuxbashssh
bobmarksie
bobmarksie

Reputation: 3646

Bash - combine 2 ssh calls into 1 (with optional and mandatory commands)

I have a script with 2 ssh commands. The SSH scripts uses SSH to log into a remote server and deletes docker images.

ssh [email protected] 'set -x &&

   echo "Stop docker images" ;
   sudo docker stop $(sudo docker ps -a -q) ;
   sudo docker rmi -f $(sudo docker images -q) ;
   sudo docker rm -f $(sudo docker ps -a -q)'

Note use of ; to separate commands (we don't care if one or more of the commands fail).

The 2nd ssh command uses SSH to log into the same server, grab a docker compose file and run docker.

ssh [email protected] 'set -x &&

   export AWS_CONFIG_FILE=/somelocation/myaws.conf &&
   aws s3 cp s3://com.somebucket.somewhere/docker-compose/docker-compose.yml . --region us-east-1 &&

   echo "Get ECR login credentials and do a docker compose up" &&
   sudo $(aws ecr get-login --region us-east-1) &&
   sudo /usr/local/bin/docker-compose up -d'

Note use of && to separate commands (this time we do care if one or more of the commands fail as we grab the exit code i.e exitCode=$?).

I don't like the fact I have to split this into 2 so my question is can these 2 sections of bash commands be combined into a single SSH call (with both ; and && combinations)?

Upvotes: 1

Views: 243

Answers (2)

Ruslan Osmanov
Ruslan Osmanov

Reputation: 21522

Although it is possible to pass a set of commands as a simple single-quoted string, I wouldn't recommend that, because:

  • internal quotation marks should be escaped
  • it is difficult to read (and maintain!) a code that looks like a string in a text editor

I find it better to keep the scripts in separate files, then pass them to ssh as standard input:

cat script.sh | ssh -T user@host -- bash -s -

Execution of several scripts is done in the same way. Just concatenate more scripts:

cat a.sh b.sh | ssh -T user@host -- bash -s -

If you still want to use a string, use a here document instead:

ssh -T user@host -- <<'END_OF_COMMANDS'
# put your script here
END_OF_COMMANDS

Note the -T option. You don't need pseudo-terminal allocation for non-interactive scripts.

Upvotes: 2

Leon
Leon

Reputation: 32544

ssh [email protected] 'set -x;

   echo "Stop docker images" ;
   sudo docker stop $(sudo docker ps -a -q) ;
   sudo docker rmi -f $(sudo docker images -q) ;
   sudo docker rm -f $(sudo docker ps -a -q) ;

   export AWS_CONFIG_FILE=/somelocation/myaws.conf &&
   aws s3 cp s3://com.somebucket.somewhere/docker-compose/docker-compose.yml . --region us-east-1 &&

   echo "Get ECR login credentials and do a docker compose up" &&
   sudo $(aws ecr get-login --region us-east-1) &&
   sudo /usr/local/bin/docker-compose up -d'

Upvotes: 0

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