What methods can be used to detect and handle errors when executing bash scripts?

The following methods are used to detect and handle errors in bash scripts:

1. Checking the return code of commands — after executing a command, the variable $? is checked. If it is not equal to 0, an error has occurred.

command
if [ $? -ne 0 ]; then
  echo "Error executing command"
fi

2. set -e — an option that causes the script to terminate when any command fails.

set -e
command1
command2 # if command1 fails, the script will stop

3. trap — allows catching signals and errors, and executing handlers.

trap 'echo "An error occurred"; exit 1' ERR

4. Using conditional operators and try-catch constructs (via functions) for more complex error handling.

5. Outputting debug information with set -x to track command execution.

Example with error handling and message output:

#!/bin/bash
set -e
trap 'echo "Error at line $LINENO"' ERR

command1
command2

By combining these methods, errors in bash scripts can be effectively detected and handled.