Skip to main content

Bash save Linux command output to a variable

How to save the output of a command to a variable in Bash script?

In Bash getting the output of a command line in terminal is sometimes necessary when doing Bash/Shell script.

For example, if need to monitor a specific service whether it is installed, running or disabled. Getting the output of the command that checks the status of specific service is quite important, so the script will know on what to execute.

If the specific output shows that the service has stopped then the script can decide to start the service, or if the output shows that a specific service or software is not installed then an option to install the software can be done.

Here’s an example on how to save the status of a specific output to a variable using Bash.

#!/bin/bash
dcommand=$(systemctl status gdm.service)
command_output=$(echo "$dcommand")
str_running='Active: active (running)'

if [[ "$command_output" == *"$str_running"* ]]; then

  echo "It's there, gdm.service is running."

#else

#do something here if not running
#a chain of commands can be done by doing like ths:
#command1;command2;sleep 3;command3
#command 2 will not execute unless command 1 is done

fi

The trick is on this line:

dcommand=$(systemctl status gdm.service) --- replace this line with any commands
command_output=$(echo "$dcommand")  --- the echo will execute the command and output is save to variable on the left

Full script:


That’s it..till next time.. Enjoy scripting.. Cheers!

================================

Free Android Apps:

Click  links below to find out more:

Excel Keyboard guide:

Heaven's Dew Fall  Prayer app for Android :



Catholic Rosary Guide  for Android:
Pray the Rosary every day, countless blessings will be showered upon your life if you recite the Rosary faithfully. 
https://play.google.com/store/apps/details?id=com.myrosaryapp

Comments

Popular posts from this blog

WMIC get computer name

WMIC get computer model, manufacturer, computer name and  username. WMIC is a command-line tool and that can generate information about computer model, its manufacturer, its username and other informations depending on the parameters provided. Why would you need a command line tool if there’s a GUI to check? If you have 20 or 100 computers, or even more. It’s quite a big task just checking the GUI to check the computer model and username. If you have remote computers, you need to delegate someone in the remote office or location to check. Or you can just write a batch file or script to automate the task. Here’s the code below on how get computer model, manufacturer and the username. Open an elevated command prompt and type:     wmic computersystem get "Model","Manufacturer", "Name", "UserName" Just copy and paste the code above, the word “computersystem” does not need to be change to a computer name. A...

Print error 016-799 - Fuji Film Xerox

016-799 Fuji Xerox or Fuji Film print error code. That shows a description error as “Print instruction Fail detected in decomposer.” The error code and error description are alien languages for users and even system administrators who are not familiar with Fuji Xerox error code. The error code is quite simple and easy to fix, if the job print goes to the printer but print out doesn’t come out. So, basically the print job was received by the printer, but the printer just doesn’t know what type of paper or what size to use or which tray to utilize for the print out. In some instances, this is just a paper mismatch but the error description; if using Windows 10 to print does not exactly points to what is the issue. First thing to check, is the paper size selected by the user to print. Example, if the printer configuration is A3 and A4 sizes only. But then the person printing the file accidentally chooses “A4 Cover” then this error 016-799 will occur. ...

PowerShell GUI with buttons, textbox and combobox

GUI makes life easier, but of course command line has a power of its own. How to add a form in PowerShell with Buttons, TextBox and ComboBox? Adding GUI forms in PowerShell must be done manually by code. It’s not that hard, you just need to love PowerShell and see what it can do to automate IT administration and makes your life easier. Anyway, code below introduces how to add GUI to PowerShell and it also illustrates how to make use of those GUI buttons and send a command to remote computers. Code to add buttons, textbox and combobox in PowerShell, and how to execute a command after the button is clicked. #initialize the main form $form = new-object Windows.forms.form $form . text = "Server Selection Form" $form . minimumSize = New-Object System.Drawing.Size ( 600 , 300 ) $form . maximumSize = New-Object System.Drawing.Size ( 600 , 300 ) #add a button to the form $button = new-object windows.forms.button $button . text...