48 lines
3.5 KiB
Markdown
48 lines
3.5 KiB
Markdown
|
|
||
|
|
## General
|
||
|
|
|
||
|
|
An alias is a way to define a new command or to modify the behavior of an existing command. It allows you to create a shortcut for a command or to change the way a command behaves. Aliases are defined using the `alias` command in the shell, and they are specific to the shell in which they are defined.
|
||
|
|
|
||
|
|
An environment variable is a value that can be passed to the operating system or to a program at runtime. It is used to configure system behavior, store information, or to communicate between processes. Environment variables are set in the shell and are used by the operating system and various programs. They can be used to store information such as the location of executables, the location of configuration files, or the current user's home directory. They can also be used to set options and customize the behavior of programs. Environment variables are typically set in a configuration file or by using a command in the shell.
|
||
|
|
|
||
|
|
|
||
|
|
## Environment Variables
|
||
|
|
|
||
|
|
Environment variables are values that can be passed to the operating system or to a program at runtime. They are used to configure system behavior, store information, or to communicate between processes.
|
||
|
|
|
||
|
|
Environment variables are typically set in the shell, and they are used by the operating system and various programs. They can be used to store information such as the location of executables, the location of configuration files, or the current user's home directory. They can also be used to set options and customize the behavior of programs.
|
||
|
|
|
||
|
|
To set an environment variable in the shell, you can use the `export` command. For example, to set the `LANG` environment variable to `en_US`, you can use the following command:
|
||
|
|
|
||
|
|
```
|
||
|
|
export LANG=en_US
|
||
|
|
```
|
||
|
|
|
||
|
|
This will set the `LANG` variable to `en_US`, which specifies that the default language for programs to use is English (United States).
|
||
|
|
|
||
|
|
To access the value of an environment variable, you can use the `echo` command and the `$` symbol. For example, to print the value of the `LANG` variable, you can use the following command:
|
||
|
|
|
||
|
|
```
|
||
|
|
echo $LANG
|
||
|
|
```
|
||
|
|
|
||
|
|
This will print `en_US`, which is the value of the `LANG` variable.
|
||
|
|
|
||
|
|
Environment variables are a powerful tool for configuring and customizing the behavior of the operating system and programs. They allow you to store and pass information between programs and scripts, and they provide a convenient way to customize the behavior of programs.
|
||
|
|
|
||
|
|
|
||
|
|
## Alias
|
||
|
|
|
||
|
|
An alias is a way to define a new command or to modify the behavior of an existing command. It allows you to create a shortcut for a command or to change the way a command behaves.
|
||
|
|
|
||
|
|
To create an alias in the shell, you can use the `alias` command. For example, to create an alias for the `ls -l` command named `ll`, you can use the following command:
|
||
|
|
|
||
|
|
```
|
||
|
|
alias ll='ls -l'
|
||
|
|
```
|
||
|
|
|
||
|
|
This will create an alias named `ll` for the `ls -l` command. Now, when you type `ll` in the shell, it will execute the `ls -l` command.
|
||
|
|
|
||
|
|
Aliases are specific to the shell in which they are defined, so they will only be available in the current shell and any child shells. If you want to create an alias that is available in all shells, you can add the `alias` command to your shell configuration file. For example, you can add it to your `.bashrc` file if you are using the Bash shell.
|
||
|
|
|
||
|
|
Aliases can be used to create shortcuts for frequently used commands, to make it easier to enter complex commands, or to modify the behavior of existing commands. They are a useful tool for customizing the shell and streamlining your workflows.
|