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What is the reason why every Linux shell script must start with a shebang line?
The shebang must be the first line because it is interpreted by the kernel, which looks at the two bytes at the start of an executable file. If these are #! the rest of the line is interpreted as the executable to run and with the script file available to that program.
How do I run a bash script silently?
To silence the output of a command, we redirect either stdout or stderr — or both — to /dev/null. To select which stream to redirect, we need to provide the FD number to the redirection operator.
How do I run a .sh file in sudo?
Therefore, to run a shell script or program as root, you need to use sudo command. However, sudo only recognizes and runs commands that exist in directories specified in the secure_path in the /etc/sudoers, unless a command is present in the secure_path, you’ll counter an error such as the one below.
What does bad interpreter mean in Bash shell?
The echo: bad interpreter: No such file or directory is most likely coming from the first line, #!… which is called shebang line. This line hints the shell what interpreter to use to run the file.
Which is shell interpreter runs a script with no…?
You’ll note that, from Bash, the first line outputs your version, while the second never says anything, no matter which shell you use. If your /bin/sh is, say, dash, then neither line will output anything when the script is executed from zsh or dash. If your /bin/sh is a link to Bash, you’ll see the first line output in all cases.
How to check if a bash script is running as root?
In addition, with proper use of sudo, you could have the script check and see if it is running as root. If not, have it recall itself via sudo and then run with root permissions. Depending on what the script does, another option may be to set up a sudo entry for whatever specialized commands the script may need.