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 …

If not quoted, it is a pattern match! (From the Bash man page: "Any part of the pattern may be quoted to force it to be matched as a string."). Here in Bash, the two statements yielding "yes" are pattern …

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 …

Oct 27, 2021 · $ command one && command two the intent is to execute the command that follows the && only if the first command is successful. This is idiomatic of Posix shells, and not only found in …

Sep 27, 2015 · What's the difference between <<, <<< and < < in bash? Here document << is known as here-document structure. You let the program know what will be the ending text, and whenever that …

Aug 1, 2019 · What does echo $? mean in shell programming? true echo $? # echoes 0 false echo $? # echoes 1 From the manual: (acessible by calling man bash in your shell) ? Expands to the exit status …

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

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 …

123 I have as bash shell script with header #!/bin/bash -e. When I run the script, it will be interrupted after the grep command runs, but when I remove the parameter -e, then the script can be run …

Modern shells such as Bash and Zsh have inherited this construct from Ksh, but it is not part of the POSIX specification. If you're in an environment where you have to be strictly POSIX compliant, stay …