To create a bash script that takes a program name as an argument and checks if there's a running process for it using pgrep, you can use the following code:

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#!/bin/bash

# Check if the user provided a program name as an argument
if [ $# -eq 0 ]; then
  # If not, print an error message and exit
  echo "Error: Please provide a program name as an argument."
  exit 1
fi

# Use pgrep to search for a running process with the given name
pgrep $1

# Check the exit code of the previous command
if [ $? -eq 0 ]; then
  # If the exit code is 0, that means a process was found, so print a message
  # indicating that the program is running
  echo "The program '$1' is currently running."
else
  # If the exit code is not 0, that means no process was found, so print a
  # message indicating that the program is not running
  echo "The program '$1' is not currently running."
fi

Save the code to a file named check_program.sh, make the file executable by running chmod +x check_program.sh, and then you can run the script by calling ./check_program.sh followed by the name of the program you want to check. For example:

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./check_program.sh bash

This will search for a running process with the name "bash" and print a message indicating whether or not it is running.

To modify the script to not show the process IDs when the program is running and to exit with a non-zero status code when the program is not running, you can use the following code:

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#!/bin/bash

# Check if the user provided a program name as an argument
if [ $# -eq 0 ]; then
  # If not, print an error message and exit
  echo "Error: Please provide a program name as an argument."
  exit 1
fi

# Use pgrep to search for a running process with the given name
pgrep $1 &> /dev/null

# Check the exit code of the previous command
if [ $? -eq 0 ]; then
  # If the exit code is 0, that means a process was found, so print a message
  # indicating that the program is running
  echo "The program '$1' is currently running."
else
  # If the exit code is not 0, that means no process was found, so print a
  # message indicating that the program is not running and exit with a non-zero
  # status code
  echo "The program '$1' is not currently running."
  exit 1
fi

This updated script will not show the process IDs when the program is running, and it will exit with a non-zero status code when the program is not running. Save the code to a file named check_program.sh, make the file executable by running chmod +x check_program.sh, and then you can run the script as before by calling ./check_program.sh followed by the name of the program you want to check. For example:

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./check_program.sh bash

This will search for a running process with the name "bash" and print a message indicating whether or not it is running. If the program is not running, the script will exit with a non-zero status code.