Bash Script

ParameterDetails-f, –fieldsField-based selection-d, –delimiterDelimiter for field-based selection-c, –charactersCharacter-based selection, delimiter ignored or error-s, –only-delimitedSuppress lines with no delimiter characters (printed as-is otherwise)–complementInverted selection (extract all except specified fields/characters–output-delimiterSpecify when it …

EscapeDetails\aA bell character.\dThe date, in “Weekday Month Date” format (e.g., “Tue May 26”).\D{FORMAT}The FORMAT is passed to `strftime'(3) and the result is inserted into the prompt string; an empty FORMAT …

Execute job once at specific time Note: at is not installed by default on most of modern distributions.To execute a job once at some other time than now, in this …

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 …