Nov 30, 2014 · So, when someone talks about bash scripting, he's using a shell, but when someone is talking about shell scripting, he isn't per se using bash. But as bash is commonly …

What do the following environment variables in Linux mean? What is $* (dollar sign followed by an asterisk)? What is $# (dollar sign next to a hash mark/number sign/octothorpe/pound sign)?

Mar 19, 2020 · What is [? [ performs a test. The purpose of [ is to test something (e.g. if some file exists) and to return exit status zero if the test succeeds, non-zero otherwise. [ is a command. …

$(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 …

Oct 20, 2019 · Bash command that prints a message on stderr echo >&2 “some text” what does it mean in shell scripting In your command posted, both messages for stdout and stderr will …

Dec 16, 2013 · More information: Bash Comparison Operators SO: What is the difference between operator “=” and “==” in Bash? Unix & Linux SE: Bash: double equals vs -eq

Nov 27, 2013 · Could someone explain to me the difference between > and >> when using shell commands? Example: ps -aux > log ps -aux >> log It seems the result is the same either way.

217 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 …

@josephmarhee: Note that the [[]] test is a Bash specific construct, and this example works just as well with the POSIX [] as used in the question. If the interpreter is explicitly given as …

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 …