# Chapter 29. Custom Commands

#### Contents:

Creating Custom Commands
Introduction to Shell Aliases
C-Shell Aliases with Command-Line Arguments
Setting and Unsetting Bourne-Type Aliases
Korn-Shell Aliases
zsh Aliases
Sourceable Scripts
Avoiding C-Shell Alias Loops
How to Put if-then-else in a C-Shell Alias
Fix Quoting in csh Aliases with makealias and quote
Shell Function Basics
Shell Function Specifics
Propagating Shell Functions
Simulated Bourne Shell Functions and Aliases

## 29.1. Creating Custom Commands

- In most shells, aliases are an easy way to shorten a long command line or do a short series of commands. Section 29.2 through Section 29.10 cover C shell aliases. Section 29.4 through Section 29.14 cover aliases in bash, pdksh, and zsh.

- All except the oldest Bourne-type shells have shell functions (Section 29.11), which are explained in Section 29.11 through Section 29.13. These are a cross between aliases and shell scripts. They're good both for shortening command lines and for running a short or long series of commands.

--JP and SJC

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