$(command) is “command substitution”. As you seem to understand, it runs the command, captures its output, and inserts that into the command line that contains the $(…); e.g.,

Aug 15, 2019 · Then we confirm the script called file_command.txt is correct. Lastly we run the script by calling bash and passing it the script name. The bashcommand is actually store as /bin/bash and it is an executable on all Ubuntu systems. Creating a file of commands saves you from adding the shebang #!/bin/bash as the first line in a script.

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I believe the OP was calling the shell script using sh instead of bash. I had a similar issue and @B.Shea comments helped, so I simply changed my shebag to read #! /usr/bin/bash and now my shell script works as expected. However, I see what you're getting at in this answer b/c the sourced commands only exist in the shell and disappear once it ...

I'm creating a simple bash script and I want to create a select menu in it, like this: $./script echo "Choose your option:" 1) Option 1 2) Option 2 3) Option 3 4) Quit And according to user's choice, I want different actions to be executed.

Aug 5, 2010 · If you want your script to run before systemd right after kernel starts, AFAIK the way is adding init=/path/to/script to the kernel command line in /boot/grub/grub.cfg or more future proof make your own menu entry in /etc/grub.d/40_custom by copying a menu entry from /boot/grub/grub.cfg and making needed changes (and running update-grub after ...

Dec 12, 2012 · Create a new script in /etc/init.d/myscript. vi /etc/init.d/myscript (Obviously it doesn't have to be called "myscript".) In this script, do whatever you want to do. Perhaps just run the script you mentioned. #!/bin/sh /path/to/my/script.sh Make it executable. chmod ugo+x /etc/init.d/myscript Configure the init system to run this script at startup.

where NNN is the set of run-levels in which you want the script active (e.g., 345 if it's active in runlevels 3, 4, and 5), and A and B are the start and stop priorities. Then chkconfig --add foo (assuming your script is named foo) will create the files …

May 25, 2012 · On Linux and other Unix-like systems you have a choice of multiple shells. The shell is responsible not only for presenting an interactive environment where it shows a prompt, but it also interprets your commands whether they are typed or loaded from a script. bash is the most common shell used as a default shell for users of Linux systems. It ...

Verify that noone except root can replace the script, e.g. by modifying the access rights of the parent folder: chown root /absolute/path/to/your/ chmod 755 /absolute/path/to/your/ Modify sudo access rights in /etc/sudoers with visudo :