bashsshquoting

How to escape the single quote character in an ssh / remote Bash command


I'm building a small set of scripts for remotely starting, stopping and checking the status of a process. The stop of these scripts should look for a process and kill it. Therefore I do:

ssh deploy@hera 'kill -9 `ps -ef | grep MapReduceNode | grep -v "grep" | awk -F " " '{print $2}' | head -n 1`'

The problem here is that the AWK tokenization step needs single quotes and these clash with the single quote utilized for executing the remote command via ssh. How can these single quotes be escaped?


Solution

  • Use

    ssh deploy@hera 'kill -9 `ps -ef | grep MapReduceNode | grep -v "grep" | awk -F " " '"'"'{print $2}'"'"' | head -n 1`'
    

    Explanation:

    ssh deploy@hera 'kill -9 `ps -ef | grep MapReduceNode | grep -v "grep" | awk -F " " '"'"'{print $2}'"'"' | head -n 1`'
                    >                               1                                   <>2<>    3     <>4<>      5      <
    

    1) First string with beginning of command: 'kill -9 `ps -ef | grep MapReduceNode | grep -v "grep" | awk -F " " '

    2) Second string with only a single ' char: "'"

    3) Third string with the print command: '{print $2}'

    4) Fourth string with another single quote: "'"

    5) Fifth string with rest of command: ' | head -n 1`'