I'm trying to learn shell scripting, and I need to understand someone else's code. What is the $? variable hold? I can't Google search the answer because they block punctuation characters.

Apr 3, 2012 · What does a dollar sign followed by an at-sign (@) mean in a shell script? For example: umbrella_corp_options $@

$(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., $ ls -ld …

Dec 14, 2024 · Shell - "Shell" is a program, which facilitates the interaction between the user and the operating system (kernel). There are many shell implementations available, like sh, Bash, …

What does $# mean in shell? I have code such as if [ $# -eq 0 ] then I want to understand what $# means, but Google search is very bad for searching these kinds of things.

What can you do with the eval command? Why is it useful? Is it some kind of a built-in function in bash? There is no man page for it..

Sep 30, 2010 · How to represent multiple conditions in a shell if statement? Asked 14 years, 9 months ago Modified 3 years, 5 months ago Viewed 1.2m times

Aug 1, 2019 · This is the exit status of the last executed command. For example the command true always returns a status of 0 and false always returns a status of 1: true echo $? # echoes …

BTW, in bash a semi-colon is a statement separator, not a statement terminator, which is a new-line. So if you only have one statement on a line then the ; at end-of-line are superfluous. Not …

Nov 15, 2010 · A bashism is a shell feature which is only supported in bash and certain other more advanced shells. It will not work under busybox sh or dash (which is /bin/sh on a lot of …