Want a command to do some composite job, but it doesn't exist? You can add new commands into your bash script
... see example [here]
from last week's course.
... here are the aliases that I'm using to provide my own extra / modified commands on our web server:
alias l.='ls -d .* --color=auto'
alias ll='ls -l --color=auto'
alias ls='ls --color=auto'
alias which='alias | /usr/bin/which --tty-only --read-alias --show-dot --show-tilde'
Shell programming is so much about bolting together other programs and utilities - and they can include other shell programs as well as code in other languages. Paramaters can be passed in from the command line, data from STDIN, and from the environment - remember to use export
if you want a shell variable / environmet variable to be shared with something you're running from your script. (written 2015-11-28)
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articlesA167 - Web Application Deployment - Shell Programming (bash) 
shell - bash. Writing conditional tests and statements - the options available - (2015-11-28) 
Bash ... some new scripts to - handling user input - (2015-11-27) 
Starting MySQL. ERROR! The server quit without updating PID file - how we fixed it. - (2015-05-06) 
Commenting out an echo killed my bash backup script - (2015-01-19) 
The Kernel, Shells and Daemons. Greek Gods in computing - (2012-07-01) 
Ruby, Perl, Linux, MySQL - some training notes - (2008-11-23) 
Selecting file names in a shell - one word or another - (2008-02-02) 
Lexical v Arithemetic testing, Bash and Perl - (2007-12-11) 
Perl and Shell coding standards / costs of an IT project - (2007-09-11) 
Work and play at Well House Manor - Football and Shell Shortcuts - (2007-08-02) 
No news is good news with Unix and Linux - (2006-08-10) 
Cottage industry or production line data handling methods - (2006-06-07) 
Shell Script for CGI on the web - (2004-09-26) 
Almost like old times - (2004-09-26)A166 - Web Application Deployment - Linux Utilities 
One line scripts - Awk, Perl and Ruby - (2016-05-20) 
Shell - Grep - Sed - Awk - Perl - Python - which to use when? - (2012-10-22) 
Shell, Awk, Perl of Python? - (2012-06-14) 
Awk v Perl - (2011-09-18) 
Finding what has changed - Linux / Unix - (2010-02-17) 
Finding text and what surrounds it - contextual grep - (2009-10-30) 
Helping new arrivals find out about source code examples - (2009-08-03) 
Using the internet to remotely check for power failure at home (PHP) - (2009-04-29) 
Conversion of c/r line ends to l/f line ends - (2008-06-28) 
awk - a powerful data extraction and manipulation tool - (2007-09-25) 
Korn shell course - (2007-09-22) 
Comparators in Linux and Unix - (2004-10-03)
Some other Articles
Progress on moving from Python 2 to Python 3 - training for both versionsPrinciples or a GUI and their practical application using wxPthonWhat teach you in a week stays with you for a decadeExtending your bash shell with aliases, functions and extra commandsWhat is make? What is gcc?Back in the saddle again - excellent open source course from Well House ConsultantsA near-empty plate of pastries - sign of a breakfast enjoyedThin application, thick objects - keep you main code simple. Example in Ruby