mac os x terminal run script suppress output

Mac os x terminal run script suppress output how to#
Mac os x terminal run script suppress output code#

The example script below displays a single use case: #!/bin/bashĮcho 'Process 1 lasts for 2s' & sleep 2 &Įcho 'Process 2 lasts for 3s' & sleep 3 &Įcho 'Process 1 ended at time $(date +%T) with exit status $?'Įcho 'Process 2 ended at time $(date +%T) with exit status $?'Ģ.

When working with multiple processes, use the PID to identify a process. Multiple Processes bash wait With PID Exampleġ. For example, wait %1 pauses for process 1 ( sleep 10) to complete. Add the job ID to indicate for which job the script should wait.Only the fastest process completes, and the script ends in ten seconds. Use the same script to test the following use cases: Since the processes run in the background, all three are completed in fifteen seconds.Ĥ. Next, make the script executable: sudo chmod +x test.shģ. Save the script as test.sh and close the file. Without any parameters, the program waits for all processes to finish.Ģ. The script prints the current time before and after the wait command. Open the text editor and add the following script with multiple processes: #!/bin/bash The background process completes any time before the wait command, and the script continues. In the terminal, change permissions to make the script executable: sudo chmod +x single_process.shģ. If the background process does not finish the first and second process, the wait command invokes a pause to wait for the background process to complete after the second process before continuing to the third process.Ģ.

Mac os x terminal run script suppress output code#

For example, add the following code in a text editor: #!/bin/bash Use the wait command to indicate by what point a background process must execute inside a script.ġ. The terminal waits for the background process to finish.Īfter 10 seconds (due to sleep 10), the console prints a Done message. Use the wait command without any parameters to pause until process completion: wait Note: If the job shows as complete, try to change the sleep time to more than 10 seconds.ģ. Confirm the job is running in the background with: jobs -l Start by opening the terminal and create a simple background process: sleep 10 &Ģ. The exit status 0 indicates the command finished successfully. The $! parameter stores the background process PID, while $? stores the exit status. To see how these three parameters work together, open a terminal window and run: sleep 10 & $? prints the exit status of the last process. Store the previous PID in a variable when working with multiple background processes.ģ. $! fetches the PID of the last background process. The ampersand sign ( &) after a command indicates a background job.Ģ. There are three additional parameters to know when working with wait in bash scripts:ġ. Terminating a program first waits for the background task to finish before quitting. Waits for only the following background process to complete and returns an exit status. Without any parameters, the wait command waits for all background processes to finish before continuing the script.Īn added PID or job ID waits for a specific process to end before continuing the script. There are different ways to use the wait command in bash scripts.

Mac os x terminal run script suppress output how to#

Note: You might also find useful our guide on how to run a bash script that features several different techniques.