
bash - What are the special dollar sign shell variables ... - Stack ...
Sep 14, 2012 · In Bash, there appear to be several variables which hold special, consistently-meaning values. For instance, ./myprogram &; echo $! will return the PID of the process which …
What does $# mean in bash? - Ask Ubuntu
Jul 25, 2017 · Furthermore, when you use bash -c, behavior is different than if you run an executable shell script, because in the latter case the argument with index 0 is the shell command used to invoke it.
shell - Bash regex =~ operator - Stack Overflow
Oct 18, 2013 · What is the operator =~ called? I'm not sure it has a name. The bash documentation just calls it the =~ operator. Is it only used to compare the right side against the left side? The right side is …
bash - What is the purpose of "&&" in a shell command? - Stack …
Oct 27, 2021 · Furthermore, you also have || which is the logical or, and also ; which is just a separator which doesn't care what happend to the command before.
bash - What does <<< mean? - Unix & Linux Stack Exchange
Take a look at the Bash man page. This notation is part of what's called a here documents & here strings. It allows you the ability to generate multi-line data input as one continuous string. The …
Bash test: what does "=~" do? - Unix & Linux Stack Exchange
Jan 27, 2017 · I realize you said “read the bash man pages” but at first, I thought you meant read the man pages within bash. At any rate, man bash returns a huge file, which is 4139 lines (72 pages) long.
bash - Shell equality operators (=, ==, -eq) - Stack Overflow
533 = and == are for string comparisons -eq is for numeric comparisons -eq is in the same family as -lt, -le, -gt, -ge, and -ne == is specific to bash (not present in sh (Bourne shell), ...). Using POSIX = is …
What does 'set -e' mean in a Bash script? - Stack Overflow
By default, Bash does not do this. This default behavior is exactly what you want if you are using Bash on the command line you don't want a typo to log you out! But in a script, you really want the …
bash - What does $ ( ... ) mean in the shell? - Unix & Linux Stack …
Sep 3, 2017 · For understanding bash code it is usually very helpful to set the -x option: set -x # within a script / function or when calling a script: bash -vx ./script.sh With loops this is a little less helpful. But …
What does the -e do in a bash shebang? - Unix & Linux Stack Exchange
All the bash command line switches are documented in man bash. -e Exit immediately if a pipeline (which may consist of a single simple command), a subshell command enclosed in parentheses, or …