Feb 20, 2011 · When going through one shell script, I saw the term "$?". What is the significance of this term?

Jan 16, 2014 · You can find a very nice reference for bash's [ aka test builtin's operators here, or by running help test in a bash shell or info bash test or info bash '[' from any shell¹. If you are using a …

Difference between $ {} and $ () in a shell script Ask Question Asked 10 years, 5 months ago Modified 10 months ago

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.

Jul 5, 2018 · The relevant man page to check for this is that of the shell itself, bash, because -f is functionality that the shell provides, it's a bash built-in. On my system (CentOS 7), the fine man page …

I would like to remove all leading and trailing spaces and tabs from each line in an output. Is there a simple tool like trim I could pipe my output into? Example file: test space at back test...

Nov 28, 2019 · First of all, avoid doing text-parsing with shell loops. It is hard to do, easy to get wrong and very hard to read. And slow. Very, very, slow. Instead, use something like awk which is …

This has confused me a lot in trying to write shell script pipelines with different logic based on some test (e.g. exiting if a file doesn't exist vs continuing the pipeline).

The shell executes a function, built-in, executable file, or script ... The shell optionally waits for the command to complete and collects the exit status. At step 6 a built-in will be executed. At step 6 eval …

A shell assignment is a single word, with no space after the equal sign. So what you wrote assigns an empty value to thefile; furthermore, since the assignment is grouped with a command, it makes …