How to prevent 'pgrep' to consider the expression it checks as containing arguments for it?

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                          I have the following script; it is supposed to start a process if it is not running:

    $ cat keepalive_stackexchange_sample.bash
    #!/bin/bash -xv
    
    # This script checks if a process is running and starts it if it's not.
    # If the process is already running, the script exits with exit code 0.
    # If the process was restarted by the script, the script exits with exit code 0.
    # If the process fails to start, the script exits with exit code 2.
    # If the first argument is "-h" or "--help", the script prints a help message and exits with exit code 10.
    #
    
    
    if [[ "$1" == "-h" ]] || [[ "$1" == "--help" ]]; then
      echo "Usage: $0 process_name"
      echo "This script checks if a process is running and starts it if it's not."
      exit 10
    fi
    
    if [[ -z "$1" ]]; then
      echo "Error: No process name provided."
      echo "Usage: $0 process_name"
      exit 12
    fi
    
    if pgrep -x -f $@ > /dev/null; then
      echo "Process '$@' is already running."
      exit 0
    else
      echo "Process '$@' is not running. Starting it..."
      if ! "$@" &> /dev/null; then
        echo "Error: Failed to start process '$@'"
        exit 2
      fi
      echo "Process '$@' started successfully"
      exit 0
    fi

This script works fine if it the process name it gets has only one word, for instance keepalive_stackexchange_sample.bash sox_authfiles_auditd_v2r.

However, if the process I'm checking has arguments, pgrep thinks these arguments are meant for it, and the script does not work as expected, for instance, if I have running:

    $ ps -ef | grep [s]ox_ | grep v2r
    username   12150     1  0 23:07 ?        00:00:00 sox_user_auditd_v2r -c
    $

and I run keepalive_stackexchange_sample.bash sox_user_auditd_v2r -c, I'll get the following error:

    + pgrep -x -f sox_user_auditd_v2r -c
    pgrep: invalid option -- 'c'
    Usage: pgrep [-flvx] [-d DELIM] [-n|-o] [-P PPIDLIST] [-g PGRPLIST] [-s SIDLIST]
            [-u EUIDLIST] [-U UIDLIST] [-G GIDLIST] [-t TERMLIST] [PATTERN]
    + echo 'Process '\''sox_user_auditd_v2r' '-c'\'' is not running. Starting it...'

and the script will run sox_user_auditd_v2r -c even though it is already running.

Any suggestion how can I have the script work on processes with arguments?
                        

Asked by boardrider (262 rep)

Feb 14, 2023, 11:23 PM
Last activity: Feb 19, 2023, 03:10 PM

How to prevent 'pgrep' to consider the expression it checks as containing arguments for it?

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