Linux command which group

Команда Which в Linux

Linux Which Command

В этом руководстве мы рассмотрим команду which.

which — команда Linux используется для определения местоположения данного исполняемого файла, который выполняется при вводе имени исполняемого файла (команды) в командной строке терминала. Команда выполняет поиск исполняемого файла, указанного в качестве аргумента, в каталогах, перечисленных в переменной среды PATH.

Что такое PATH

В Linux PATH это переменная окружения, которая сообщает оболочке и другим программам, в каких каталогах искать исполняемые файлы. Он состоит из списка разделенных двоеточиями абсолютных путей к каталогам, содержащим исполняемые файлы.

Чтобы просмотреть содержимое вашей переменной PATH, используйте команду echo с $PATH аргументом:

Вывод будет выглядеть примерно так:

Как использовать which команду

Синтаксис which команды следующий:

Например, чтобы найти полный путь команды ping , вы должны набрать следующее:

Результат будет примерно таким:

Вы также можете указать несколько аргументов which команды:

Вывод будет включать полные пути к обоим netcat и uptime исполняемым файлам :

Поиск выполняется слева направо, и если в каталогах, перечисленных в PATH переменной пути, найдено более одного совпадения , which будет напечатано только первое. Чтобы распечатать все совпадения, используйте -a опцию:

Вывод покажет два полных пути к touch команде :

Обычно один из исполняемых файлов предназначен только symlink для другого, но в некоторых случаях в разных местах могут быть установлены две версии одной и той же команды или совершенно разные команды с одним и тем же именем.

Вывод

Команда which используется для поиска команды путем поиска исполняемого файла команды в каталогах, указанных в переменной среды PATH .

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Linux/UNIX: Find Which Groups Do I Belong To

H ow do I find out in which groups do I belong to on Linux or Unix-like operating systems? How can I find out my group membership so that I can determine access to devices and files on Linux/Unix operating systems?

A user can be in any number of groups apart from his/her default group. Groups are created and managed by root user. You cannot edit or modify your own ownership. However Linux allows you to view in which groups you are by using the groups command. This is useful to find out if you can access:

Tutorial details
Difficulty level	Easy
Root privileges	No
Requirements	None
Est. reading time	1m

1. Directories
2. Files
3. Devices
4. Burn CD/DVD
5. Backup files
6. Restart system services
7. Play music and video and more.

Task: Display or print the groups a user is in

Type the whoami command to display your user ID:
$ whoami
Sample outputs:

See which groups your Linux/Unix user belongs to

Type the groups command to show which groups your Unix or Linux user belongs to:
$ groups
Sample outputs:

So my default group is vivek and I am a member of dialout, cdrom, floppy, audio, video plugdev group. You can also use id command to print both numeric and name based group id:
$ id
Output:

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The id command is preferred command to list groups a user belongs to On Linux or Unix-like operating systems:
$ groups
$ groups userNameHere
$ id -Gn
$ id -Gn userNameHere
Sample outputs:

Animated gif 01: groups and id command to display groups a user belongs to

See also

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Linux Show All Members of a Group Command

Linux Show All Members of a Group Commands

Tutorial details
Difficulty level	Easy
Root privileges	Yes
Requirements	None
Est. reading time	1m

1. /etc/group file – User group file
2. members command – List members of a group
3. lid command (or libuser-lid on newer Linux distros) – List user’s groups or group’s users

There are two types of groups in Linux:

• Primary group – is the main group that is associated with user account. Each user is a member of exactly one primary group.
• Secondary group – used to provide additional rights to user. For example, access to the dvd/cdrom drive can be granted with help of cdrom group.

Linux: List all members of a group using /etc/group file

Use the grep command or cat command/more command as follows:
$ grep ‘grpup-name-here’ /etc/group
$ grep ‘ftponly’ /etc/group
$ cat /etc/group
$ less /etc/group
$ grep -i —color ‘ftponly’ /etc/group

We can also type the compgen command or getend command to list all group names on Linux:
$ compgen -g
$ getent group
To get just a list of all members of a group called ftponly , type the following awk command:

Display group memberships for each Linux user

Want to see group memberships for each given USERNAME under Linux? The syntax is as follows for the groups command:
groups
groups
groups vivek
The following outputs indicates that the user named ‘vivek’ is part of four groups including ‘vivek’ primary group:

Linux List all members of a group using members command

Warning: members command is not installed on most Linux distros. Use yum command or apt-get command/apt command to install the same:
$ sudo apt-get install members

To outputs members of a group called ftponly, enter:
$ members
$ members ftponly

Fig. 01: members command in action to list members in a group

How to list all users in a Linux group using lid command

You can displays information about groups containing user name, or users contained in group name using lid command as follows.

Warning: lid command is not installed on most distros. Use yum command or apt-get command to install the same:
$ sudo apt-get install libuser

To see users contained in group named ‘ftponly’:

# lid -g ftponly
Please note that newer version of libuser renamed the lid command to libuser-lid . Thus, use it as follows:
$ sudo libuser-lid -g ftponly
Sample outputs:

To show information about groups containing user named ‘nixcraft’:

Use lid command or libuser-lid command on Linux to show all members of a group named nixcraft:
# lid nixcraft
OR
$ sudo libuser-lid nixcraft
Sample outputs:

See lid command man page for more information.

How to list groups in Linux

To see all users, run less command/more command:
less /etc/group
OR
more /etc/group
Another option is to type the following getent command:
getent group
For example, locate the members of a group with the name vboxusers, run:
getent group vboxusers
Sample outputs indicating vivek and raj users are part of vboxusers group:

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Finally, you can use the id command to display real and effective user and group IDs:
id
id vivek
id -nG raj # show all group IDs for raj user
id -ng raj # show only effective group ID for raj user

Conclusion

Now you know how to use various Linux commands to show all members of a group. I suggest you read the man pages for more info by typing the following man command:
$ man libuser-lid
$ man members

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Команда which в Linux [с примерами]

Другими словами, если вам интересно, где именно находится определенная программа, просто используйте which. Команда Linux имеет простой синтаксис:

Давайте посмотрим, как использовать эту простую, но полезную команду.

Linux, Примеры команды which

Допустим, вы хотите знать, где находится исполняемый файл Java, используйте команду:

Вывод может быть таким:

$ which java
/usr/bin/java

Обратите внимание, что работает только с исполняемыми файлами. Таким образом, вы должны использовать which только с аргументом. Например, вы устанавливаете Java с помощью пакета JDK, но не запускаете команду с именем «jdk», вы запускаете «java». Таким образом, вы используете команду which на Java, а не JDK.

Если команда which не находит исполняемый файл в текущем пути, она ничего не возвращает.

Использование команды which с несколькими исполняемыми файлами

Вы можете предоставить более одного аргумента для команды which:

Вывод для нас был такой:

$ which man java python nada
/usr/bin/man
/usr/bin/java
/usr/bin/python

Вы заметили что-то здесь? Мы дали ему четыре аргумента, но результат отображается только для трех из них. Это потому, что «nada» не исполняемый файл. Там нет вывода для which.

Показать все пути с командой which

Команда which в Linux имеет только одну опцию -a. По умолчанию эта команда печатает только один путь для своих аргументов.

Если программа имеет исполняемый файл в двух местах, например, в /usr/bin/program и в /usr/local/bin/program, вы можете отобразить оба пути с помощью опции -a.

Статус вывода команды which

Если вы используете команду which в скрипте bash, вам может потребоваться узнать ее состояние завершения.

Команда which имеет следующий статус выхода:

• 0 – все аргументы найдены и выполняются
• 1 – один или несколько аргументов не существуют или не выполняются
• 2 – если указан неверный параметр

Это все, что вам нужно знать о команде which в Linux. Если у вас есть вопросы или предложения, дайте нам знать в комментариях ниже.

Если вы нашли ошибку, пожалуйста, выделите фрагмент текста и нажмите Ctrl+Enter.

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How To Find Out Which Groups A User Belongs To In Linux

A Linux group is a collection of one or more users with identical permission requirements on files and directories. An user can be a member of more than group at a time. In Linux, each group information is stored in the «/etc/group» file. In this tutorial, we will see all the possible ways to easily find out which groups a user belongs to in Linux and Unix-like operating systems.

Finding out the groups to which a user account belongs will be helpful in many occasions. For instance, the other day I was installing Dropbox on my Ubuntu server. When configuring Dropbox, I had to enter my current user name and the group name. You could also be in a situation where you need to identify the groups a user belongs to. If so, use any one of the following methods to know what group a user is in.

Find out which Groups a user belongs to in Linux

There are many ways to list the groups that a Linux user is a member of. The most commonly used method is by using groups command.

Method 1 — groups command

The groups command displays the current group names and the users belongs to those groups in Linux and Unix-like operating systems.

First, let us find how many groups are there in our Linux system.

To find the list of available in Linux, run the groups command without any arguments like below:

Sample output:

List available groups in Linux

As you can see in the above output, there are currently 12 groups in my system.

Now, find out which groups a specific user, for example sk, belongs to. To do so, enter «groups» command followed the username like below:

Sample output:

Find out which Groups a user belongs to in Linux using groups command

Here, sk is my username and the user sk is the member of all of the above groups. You might have noticed that «sk» is listed twice. Because, I have used the same name for both username and group name.

For more details about «groups» command, refer man pages.

Method 2 — id command

The another way to identify the groups a user is in is by using «id» command. The id command is used to print user and group information for the specified USER. If the USER is not specified, it will print the information for the current user.

To identify all the groups that a user belongs to using «id» command, run:

Replace sk with your username.

Sample output:

Find out which Groups a user belongs to in Linux using id command

As you see here, the id command not only lists the groups that user is member of, but also group id and user id (UID and GID) of the given user and the groups. It has more verbose output than the «groups» command, so if you need the group id/user id use this!

If you don’t want to print the numbers, simply use -Gn flag like below:

For more details, refer the man pages.

Method 3 — using «/etc/group» file

As I stated already, the /etc/group file contains the information about each group in a Linux system. You can find which groups the given user belongs to from the contents of the /etc/group file with the help of «grep» command as shown below:

Sample output:

If you want to exclude the group ids and the username and display only the group names, pipe the «grep» command’s output to «awk» command like below:

Sample output:

Find which Groups a user belongs to in Linux using grep and awk commands

Method 4 — getent command

The «getent» command displays entries from databases supported by the Name Service Switch libraries, which are configured in /etc/nsswitch.conf file.

We can list all available groups and their members in a Linux system using getent command like below:

To find which groups a specific user (E.g. sk) belongs to, run:

Sample output:

If you want to display only the groups excluding all other details, filter the output with «grep» and «awk» commands like below:

Find which Groups a user belongs to in Linux using getent, grep and awk commands

List all users belongs to a group in Linux

We can also find the list of all users that belongs to a specific group. For instance, the following command displays the users which are belongs to the group named storage.

Easy, right? Indeed. Finding which groups a user belongs and the users of a specific group is super easy!!

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