What is nohup

nohup stands for "no hang up." It is a command used in Unix-like operating systems to run another command or script in the background, and it ensures that the command continues running even if you log out or the terminal is closed. In other words, nohup is used to detach a process from the terminal and prevent it from being terminated when you exit the shell.

The basic syntax for using nohup is as follows:

bash

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nohup command-to-run &

command-to-run is the command or script you want to run.

& is used to run the command in the background.

Here's why you might use nohup:

Running long-running tasks: You can use nohup to run tasks or processes that will take a long time to complete. This way, you don't have to keep the terminal open, and the process will continue running even if you log out.

Running processes on remote servers: When you log out of an SSH session on a remote server, any processes you started will be terminated. Using nohup, you can keep them running.

Preventing processes from being terminated: Even if a process is accidentally started in a terminal session, nohup can be used to prevent it from being terminated when you close the terminal.

nohup also redirects the output of the command to a file named nohup.out in the current directory by default. You can specify a different output file like this:

bash

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nohup command-to-run > output-file.log &

This can be helpful for logging the output of long-running processes.

Keep in mind that while nohup allows a process to continue running in the background, it does not provide advanced process management features like process control or monitoring. For more advanced process management, tools like tmux or screen may be more suitable.

references:

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