How to get user name linux

How do I get the current user’s username in Bash?

It seems none of the methods proposed so far work without relying on $USER or invoking a separate process. Is there no bash builtin to get the username without invoking a separate process?

When you’ve heard a command but aren’t sure how to use it, checking man whoami is usually a good first stop to check for documentation.

14 Answers 14

On the command line, enter

Just a quick note that $USER and whoami return different values if your running a command through ssh as another user. whoami returns the OS user and $USER returns the ssh user.

In some cases, $USER is not set at all. Worse, it is just an environment variable, so it can be overridden by the user: USER=thisisnotmyname bash -c ‘echo $USER’ # prints thisisnotmyname

@SethMMorton I realise I made the issue sound worse than it usually is. To answer the question, though, using whoami (as you suggested) eliminates the problem altogether, assuming overridden environment variables is a potential issue in your context.

«current username» is slightly ambiguous. What do you want to get when running under sudo? «echo $USER» produces the name I logged in as whether run under sudo or not, while «whoami» returns «root» when run under sudo and my actual login name otherwise. Scripts that need to be run as sudo are more likely to be in that minority of scripts that have need of your login name rather than «root».

An alternative to whoami is id -u -n .

id -u will return the user id (e.g. 0 for root).

Unless I’m mistaken this would be the way to go if portability is a concern as the id command and -u and -n flags are a part of posix

This really should be the accepted answer. «$» and whoami both depend on how you log in. Specifically, login shells and sudo will set $USER, and whoami looks at the user attached to stdin. However, if you are running a batch job from cron, or you are running a startup script as a different user than root, then these will either output the wrong user (root) or nothing at all. This answer will return the correct value regardless by looking at process’s user ID.

if you tried the command before adding untrue comments, you would see that the -n argument prints the username, just like the original question asked. see the following: id -u -n prints brett — even on darwin.

A great alternative when checking on live container instances with very few command line apps installed. whoami isn’t installed on many of the lite images out there.

Use the standard Unix/Linux/BSD/MacOS command logname to retrieve the logged in user. This ignores the environment as well as sudo, as these are unreliable reporters. It will always print the logged in user’s name and then exit. This command has been around since about 1981.

My-Mac:~ devin$ logname devin My-Mac:~ devin$ sudo logname Password: devin My-Mac:~ devin$ sudo su - My-Mac:~ root# logname devin My-Mac:~ root# echo $USER root 

This was particularly helpful to me over whoami or $USER as I am using sudo to execute as another user, but want the original user not the sudo user.

BTW this is the best answer, not only for me personally but also to the purpose of the OP’s question.

A hack the I’ve used on Solaris 9 and Linux and which works fine for both of them:

This snippet prints the name of the user with the current EUID.

NOTE: you need Bash as the interpreter here.

On Solaris you have problems with methods, described above:

• id does not accept the -u and -n parameters (so you will have to parse the output)
• whoami does not exist (by default)
• who am I prints owner of current terminal (ignores EUID)
• $USER variable is set correctly only after reading profile files (for example, /etc/profile )

Why do you need bash as the interpreter? Nothing in the command line shown seems to be specific to any shell. In fact, why even include the pipe through awk? As far as I can tell, your ps command is everything required to display the owner of the current shell’s pid.

For us as humans to disregard the superfluous information is natural. The awk portion isolates the desired data— for variables or in general the computer that can’t make on the fly assumptions just yet at this rudimentary level.

On Solaris, use command -p id (from a POSIX shell) or /usr/xpg4/bin/id . More generally, on Solaris, you’d want to modify your environment to put yourself in a POSIX environment (with something like PATH= getconf PATH` and be sure to run /usr/xpg4/bin/sh ) to avoid being stuck with commands from the 70s/80s.

1. id prints the user id along with the groups. Format: uid=usernumber(username) .
2. whoami gives the current user name

$whoami isn’t available as a variable in bash. You need to do either $(whoami), or `whoami` to actually execute the whoami command!

When root (sudo) permissions are required, which is usually 90%+ when using scripts, the methods in previous answers always give you root as the answer.

To get the current «logged in» user is just as simple, but it requires accessing different variables: $SUDO_UID and $SUDO_USER .

echo $SUDO_UID echo $SUDO_USER 

myuid=$SUDO_UID myuname=$SUDO_USER 

In Solaris OS I used this command:

$ who am i # Remember to use it with space. 

On Linux- Someone already answered this in comments.

Those 2 commands display 2 different informations. Just log as root, use «su — xxx», and see for yourself.

. gets you the regular user (if non-sudo) → or ← the regular user behind the current sudo call.

How could i do it in nested quotes? e.g. my_var=»$(‘/some/path/to/$/more/path’ ‘and/something/else’)»

The current user’s username can be gotten in pure Bash with the $ parameter expansion (introduced in Bash 4.4):

The : built-in (synonym of true ) is used instead of a temporary variable by setting the last argument, which is stored in $_ . We then expand it ( \u ) as if it were a prompt string with the P operator.

This is better than using $USER , as $USER is just a regular environmental variable; it can be modified, unset, etc. Even if it isn’t intentionally tampered with, a common case where it’s still incorrect is when the user is switched without starting a login shell ( su ‘s default).

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5 Methods to Get Current User Name in Linux/Unix Shell Script

Learn how to retrieve the current user name in a Linux/Unix shell script with 5 different methods. Get key points, important points, and helpful points to ensure a thorough understanding of shell get user name bash.

• Using $USER or $USERNAME Variables
• Checking Current Shell Name
• Obtaining Username from UID Using Cut Command
• Using Whoami and Logname Commands
• Displaying User Information Using ID Command
• Other code samples for retrieving current user name in a Linux/Unix shell script
• Conclusion
• How to get username in shell script?
• How do I get filename in bash?
• How to get user name in Linux?
• How to print current user in Linux?

As a Linux/Unix shell script developer, it’s important to know how to retrieve the current user name in your scripts. There are several methods to accomplish this, and in this blog post, we will explore five of them. By the end of this article, you should be able to confidently retrieve the current user name in your Linux/Unix shell scripts.

Using $USER or $USERNAME Variables

The $USER and $USERNAME variables are widely used in Linux/Unix systems and store the name of the current user account. To display the current user account in your shell script, simply use “echo $USER” or “echo $USERNAME”. However, it’s important to note that the value of these variables should not be used for security decisions. For example, if your script is checking if the current user has permission to access a file, relying solely on the $USER or $USERNAME variable is not secure.

Checking Current Shell Name

Another method to get the current user name in a Linux/Unix shell script is to display the current shell name. You can do this using the command “ps -p $$”, which will display the current shell name. Alternatively, you can print the shell for the current user by using “echo $SHELL” in your shell script.

Obtaining Username from UID Using Cut Command

The UID, or User ID, is a unique identifier assigned to each user account in Linux/Unix systems. In order to retrieve the username from the UID, you can use the “cut” command. The command “getent passwd $UID | cut -d: -f1” will display the username for the specified UID.

Using Whoami and Logname Commands

The “whoami” command prints the effective username of the current user, while the “logname” command prints the user’s login name. An example script using the “logname” command is “by_logname”. You can use these commands in your shell script to retrieve the current user name.

Displaying User Information Using ID Command

The “id” command prints user and group information for the specified user. To display the current user’s information, use “id -un” in your shell script. Additionally, the “id -u” command can be used to display the UID of the current user.

Other code samples for retrieving current user name in a Linux/Unix shell script

In Shell , for instance, bash get username code example

whoami cd /home/USERNAME/Desktop

Conclusion

In this blog post, we have explored several methods to get the current user name in a Linux/Unix shell script. We covered key points such as using $USER or $USERNAME variables, checking the current shell name, and obtaining the username from the UID using the cut command . We also highlighted important points such as the fact that the value of $USER or $USERNAME should not be used for security decisions and that the /etc/passwd file stores user information, including the username. Finally, we provided helpful points such as using the “who” command to display information about users currently logged in and the “id” command to print the UID, GID, and groups of a specified user.

It’s important to choose the method that best suits your needs, depending on the situation and the purpose of your script. With this knowledge, you should be able to confidently retrieve the current user name in your Linux/Unix shell scripts. Remember to always prioritize security when handling user information.

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How to get the logged in user’s real name in Unix?

I’m looking to find out the logged in user’s real (full name) to avoid having to prompt them for it in an app I’m building. I see the finger command will output a columned list of data that includes this and was wondering if it makes sense to grep through this or is there an easier way? None of the switches for finger that I’ve found output just the real name. Any thoughts would be much appreciated.

Right on Beta, that worked beautifully. Do you think that this is safe if there is more than one logged in user? Specifically does your sed magic above return all real name’s or just the first one it encounters? Thanks!

Or: finger blah | grep Name | awk -F «Name:» ‘‘ These will work fine if there are multiple users. It just pulls the one specified.

7 Answers 7

getent passwd `whoami` | cut -d : -f 5 

( getent is usually preferable to grepping /etc/passwd ).

getent passwd "$USER" | cut -d: -f5 | cut -d, -f1 

This first fetches the current user’s line from the passwd database (which might also be stored on NIS or LDAP)

In the fetched line, fields are separated by : delimiters. The GECOS entry is the 5th field, thus the first cut extracts that.

The GECOS entry itself is possibly composed of multiple items — separated by , — of which the full name is the first item. That’s what the second cut extracts. This also works if the GECOS entry is lacking the commas. In that case the whole entry is the first item.

You can also assign the result to a variable:

fullname=$( getent passwd "$USER" | cut -d: -f5 | cut -d, -f1 ) 

Or process it further directly:

echo "$( getent passwd "$USER" | cut -d: -f5 | cut -d, -f1 )'s home is $HOME." 

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