trap:tldr:bc168

trap: Set a trap to execute commands when one or more signals are detected.

trap

$ trap 'echo "Caught signal ${SIGHUP}"' ${SIGHUP}

try on your machine

The command trap 'echo "Caught signal ${SIGHUP}"' ${SIGHUP} sets up a trap in a shell script to capture the SIGHUP (hangup) signal.

Here's a breakdown of the command:

trap: trap is a built-in command in most Unix-like operating systems. It allows you to define actions to be taken when a signal is received by the script or shell.
'echo "Caught signal ${SIGHUP}"': This is the action to be taken when the specified signal (SIGHUP in this case) is received. In this case, it simply echoes a message to the console displaying the caught signal. ${SIGHUP} is the variable representing the SIGHUP signal number.
${SIGHUP}: This is the signal to trap. In this case, it is specified as SIGHUP, which is the signal sent to a process when its controlling terminal is closed or when the controlling process is terminated.

This explanation was created by an AI. In most cases those are correct. But please always be careful and never run a command you are not sure if it is safe.

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