Declare weakly typed variables declare is an internal command of bash. (internal command use help for displaying “manpage”). It is used to show and define variables or show function bodies. …

Hello World # create the co-process coproc bash # send a command to it (echo a) echo 'echo Hello World' >&"${COPROC[1]}" # read a line from its output read line …

color-output.sh In the opening section of a bash script, it’s possible to define some variables that function as helpers to color or otherwise format the terminal output during the run …

Start an interactive shell bash Detect type of shell shopt -q login_shell && echo 'login' || echo 'not-login' Introduction to dot files In Unix, files and directories beginning with a …

There are some means to chain commands together. Simple ones like just a ; or more complex ones like logical chains which run depending on some conditions. The third one …

Parameter | Meaning-p List currently installed traps-l List signal names and corresponding numbers Introduction: clean up temporary files You can use the trap command to “trap” signals; this is the …

In Bash 4.2, a shell built-in time conversion for printf was introduced: the format specification %(datefmt)T makes printf output the date-time string corresponding to the format string datefmt as understood …

Parameter Details IFS Internal field separator-x Print commands and their arguments as they are executed (Shell option) What, when and Why? When the shell performs parameter expansion, command substitution, variable …

Parameter DetailsPATH Path environment variable Add a path to the PATH environment variable The PATH environment variable is generally defined in ~/.bashrc or ~/.bash_profile or /etc/profile or ~/.profile or/etc/bash.bashrc (distro …

Using |& |& connects standard output and standard error of the first command to the second one while | only connectsstandard output of the first command to the second command.In …