How to use the command 'pidof' (with examples)

The ‘pidof’ command is used to get the process ID(s) of a running process based on its name. It is a Linux command that can be used to find the process ID(s) of a process, which can then be used for various operations like killing the process or checking its status. The ‘pidof’ command can be useful in scripting and automation tasks, as it allows you to perform actions on specific processes by their name.

Use case 1: List all process IDs with given name

Code:

pidof bash

Motivation: This use case is useful when you want to know the process IDs of all running instances of a particular process. For example, if you want to find all the running instances of the ‘bash’ shell, you can use this command.

Explanation: The ‘pidof’ command is followed by the name of the process you want to find the process IDs for. In this case, we are using ‘bash’ as the example process name. The command will list all the process IDs of currently running ‘bash’ processes.

Example output:

1234 5678 91011

Use case 2: List a single process ID with given name

Code:

pidof -s bash

Motivation: Sometimes, you may only be interested in getting a single process ID for a particular process. This is especially useful when you want to perform actions on a specific instance of a process, rather than all running instances.

Explanation: The ‘-s’ option is used to specify that only a single process ID should be returned. In this case, we are using the ‘bash’ process as an example. The command will return the process ID of any running ‘bash’ process.

Example output:

1234

Use case 3: List process IDs including scripts with given name

Code:

pidof -x script.py

Motivation: This use case is helpful when you want to find the process ID(s) of a particular script running on your system. It allows you to identify and perform actions on running scripts based on their filenames.

Explanation: The ‘-x’ option is used to include scripts in the search for process IDs. In this case, we are using ‘script.py’ as an example script name. The command will list the process ID(s) of any running instance of ‘script.py’, along with other processes.

Example output:

1234 5678

Use case 4: Kill all processes with given name

Code:

kill $(pidof name)

Motivation: Killing all processes with a given name can be helpful in situations where you want to stop all instances of a particular process. This can be useful for cleanup or when dealing with processes that may be running in the background.

Explanation: The ‘kill’ command is used to send a signal to a process. In this case, we are using ‘$(pidof name)’ to get the process IDs and passing them to the ‘kill’ command. By replacing ’name’ with the desired process name, the command will kill all the processes that match that name.

Example output: N/A (the command does not produce output, but it will stop the specified processes)

Conclusion:

The ‘pidof’ command can be a useful tool for managing processes on a Linux system. It allows you to easily find the process ID(s) of a process based on its name, enabling you to perform various operations on those processes. With the different options available, you can customize the output and target specific processes based on their names.