How to create and use aliases in Zsh

Repeated option-heavy commands are easy to mistype in an interactive Zsh terminal, especially when the same command is run many times during one session. A Zsh alias gives that command a short name for simple replacements such as a preferred ls format, while shell functions are better for shortcuts that need arguments, tests, or branching.

The alias builtin stores a name-to-command replacement in the current shell. A temporary alias starts working as soon as it is defined, and unalias removes it from that shell without changing any startup file.

Persistent aliases belong in ~/.zshrc because Zsh reads that file for interactive shells. Reload the file with source or open a new terminal, then confirm both the stored alias definition and the command output before relying on the shortcut.

Steps to create and use Zsh aliases:

Define a temporary alias in the current terminal.
```
$ alias ll='ls -lh'
```
Do not put spaces around the equals sign. Quote the replacement command when it includes spaces or options.
Confirm the alias definition.
```
$ alias ll
ll='ls -lh'
```
Zsh prints alias definitions without the word alias in the output. The line still means ll expands to ls -lh.
Run the alias against a directory.
```
$ ll ~/projects/demo
total 0
-rw-r--r-- 1 operator operator 0 Jun  5 02:11 report.txt
```
Zsh expands aliases in interactive shells. Use a function or the full command inside scripts instead of depending on user aliases.

Related: How to create a function in Zsh
Remove the temporary alias when the shortcut is no longer needed.
```
$ unalias ll
```
Add the alias to ~/.zshrc.
```
$ nano ~/.zshrc
```
~/.zshrc
```
alias ll='ls -lh'
```
Keep interactive aliases in ~/.zshrc. Use a function when the shortcut needs parameters, branching, or more than one command.

Related: How to configure Zsh startup files
Related: How to create a function in Zsh
Check ~/.zshrc for syntax errors.
```
$ zsh -n ~/.zshrc
```
No output from zsh -n means Zsh parsed the file without finding a syntax error.
Reload ~/.zshrc in the current terminal.
```
$ source ~/.zshrc
```
Confirm that the persistent alias loaded.
```
$ alias ll
ll='ls -lh'
```

Run the alias after reloading the startup file.

$ ll ~/projects/demo
total 0
-rw-r--r-- 1 operator operator 0 Jun  5 02:11 report.txt