Shell script running in the background

1. Use the ampersand to execute commands in the background

You can add an ampersand after a Linux command or script to execute the command or script in the background, for example:.

$ ./my-shell-script.sh &

 

2. Use nohup to execute commands in the background

After using the & symbol to execute a command or script in the background, if you log out, the command will be automatically terminated. To avoid this situation, you can use the nohup command as follows:

$ nohup ./my-shell-script.sh &

 

3. Use screen to execute commands

After executing a command in the background through nohup and the & symbol, the command will continue to be executed even if you log out. However, you cannot reconnect to this session. To reconnect to this session, you can use the screen command. .

The Linux screen command provides the function of separating and reconnecting a session. When you reconnect to this session, your terminal is exactly the same as when you detached.

 

4. Use at to execute a command as a batch

Using the at command, you can make a command run on a specified date and time. For example, to execute a backup script in the background at 10 AM tomorrow, execute the following command:

$ at -f backup.sh 10 am tomorrow

 

Performing certain tasks in batch mode requires certain options to be enabled. The following article will give a detailed explanation:.

• How To Capture Unix Top Command Output to a File in Readable Format

• Unix bc Command Line Calculator in Batch Mode

• How To Execute SSH and SCP in Batch Mode (Only when Passwordless login is enabled)

5. Use watch to execute a command continuously

To continuously execute a command at a fixed interval, you can use the watch command, as shown below:

$ watch df -h