Overview
whoami is an abbreviation for 'Who am I?', a command that prints the account name of the user currently executing commands in the shell. It helps to clearly identify which user has privileges when using the `sudo` command or switching to another user (`su`). This command prints the username based on the value of the `$EUID` environment variable and returns the same result as `id -un`.
Key Features
The main features of the `whoami` command are as follows:
- Prints the name of the currently logged-in user.
- Prints the effective user ID, which may differ from the actual logged-in user (`logname`).
- Often used in scripts to check the current executing user.
- A simple command with very few options.
Differences Between whoami and who
Both `whoami` and `who` display user information, but they differ in the scope of information provided.
- whoami: Only prints the name of the user currently executing the command.
- who: Prints the names, login times, terminal information, and more for all users currently logged into the system.
Main Options
The `whoami` command is very simple, primarily using basic help options like `-h` or `-v`.
1) Help
Generated command:
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Description:
`whoami` Executes the command.
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Usage Examples
Learn the functions of the `whoami` command through various usage examples.
Check Current Username
whoamiPrints the name of the currently logged-in user.
Check After Switching to Root User
whoami
sudo whoamiAfter gaining root privileges with the `sudo` command, running `whoami` will output `root` as the effective username currently executing the command.
Check After Switching to Another User
whoami
su guest
whoamiAfter switching to another user, `guest`, with the `su` command, running `whoami` will output `guest`.
Installation
whoami is part of the `coreutils` package and is included by default in most Linux distributions. No separate installation is required.
Tips & Cautions
Here are some points to note when using the `whoami` command.
Tips
- In scripts, you can use `if [ "$(whoami)" == "root" ]; then ... fi` to check if the current user is `root`.
- `whoami` outputs the same information as `id -un`. The `id` command provides more detailed user information, such as UID and GID.