{"id":664,"date":"2018-07-11T06:51:19","date_gmt":"2018-07-11T06:51:19","guid":{"rendered":"http:\/\/hyderabadwebhosting.in\/blog\/?p=664"},"modified":"2018-08-01T21:42:26","modified_gmt":"2018-08-01T21:42:26","slug":"complete-guide-to-useradd-command-in-linux","status":"publish","type":"post","link":"https:\/\/hyderabadwebhosting.in\/blog\/complete-guide-to-useradd-command-in-linux\/","title":{"rendered":"Complete Guide to \u201cuseradd\u201d Command in Linux"},"content":{"rendered":"

The Complete Guide to \u201cuseradd\u201d Command in Linux<\/span><\/p>\n

We all are aware about the most popular command called \u2018useradd\u2018 or \u2018adduser\u2018 in Linux. There are times when a Linux System Administrator asked to create user accounts on Linux with some specific properties, limitations or comments.<\/span><\/p>\n

In Linux, a \u2018useradd\u2018 command is a low-level utility that is used for adding\/creating user accounts in Linux and other Unix-like operating systems. The \u2018adduser\u2018 is much similar to useradd command, because it is just a symbolic link to it.<\/span><\/p>\n

In some other Linux distributions, useradd command may comes with lightly difference version. I suggest you to read your documentation, before using our instructions to create new user accounts in Linux.<\/span><\/p>\n

When we run \u2018useradd\u2018 command in Linux terminal, it performs following major things:<\/span><\/p>\n

* It edits \/etc\/passwd, \/etc\/shadow, \/etc\/group and \/etc\/gshadow files for the newly created User account.<\/span><\/p>\n

* Creates and populate a home directory for the new user.<\/span><\/p>\n

* Sets permissions and ownerships to home directory.<\/span><\/p>\n

In this article we will show you the most used 10 useradd commands with their practical examples in Linux. We have divided the section into two parts from Basic to Advance usage of command.<\/span><\/p>\n

1. How to Add a New User in Linux<\/span><\/strong><\/p>\n

To add\/create a new user, all you\u2019ve to follow the command \u2018useradd\u2018 or \u2018adduser\u2018 with \u2018username\u2019. The \u2018username\u2019 is a user login name, that is used by user to login into the system.<\/span><\/p>\n

Only one user can be added and that username must be unique (different from other username already exists on the system).<\/span><\/p>\n

For example, to add a new user called \u2018hydhost\u2018, use the following command<\/span><\/p>\n

\"\"<\/a><\/p>\n

When we add a new user in Linux with \u2018useradd\u2018 command it gets created in locked state and to unlock that user account, we need to set a password for that account with \u2018passwd\u2018 command.<\/span><\/p>\n

\"\"<\/a><\/p>\n

Once a new user created, it\u2019s entry automatically added to the \u2018\/etc\/passwd\u2018 file. The file is used to store users information and the entry should be.<\/span><\/p>\n

manoj:x:504:504:tecmint:\/home\/tecmint:\/bin\/bash<\/pre>\n
The above entry contains a set of seven colon-separated fields, each field has it\u2019s own meaning. Let\u2019s see what are these fields:<\/span><\/p>\n
Username: User login name used to login into system. It should be between 1 to 32 charcters long.<\/span><\/p>\n
Password: User password (or x character) stored in \/etc\/shadow file in encrypted format.<\/span><\/p>\n
User ID (UID): Every user must have a User ID (UID) User Identification Number. By default UID 0 is reserved for root user and UID\u2019s ranging from 1-99 are reserved for other predefined accounts. Further UID\u2019s ranging from 100-999 are reserved for system accounts and groups.<\/span><\/p>\n
Group ID (GID): The primary Group ID (GID) Group Identification Number stored in \/etc\/group file.<\/span><\/p>\n
User Info: This field is optional and allow you to define extra information about the user. For example, user full name. This field is filled by \u2018finger\u2019 command.<\/span><\/p>\n
Home Directory: The absolute location of user\u2019s home directory.<\/span><\/p>\n
Shell: The absolute location of a user\u2019s shell i.e. \/bin\/bash.<\/span><\/p>\n
2. Create a User with Different Home Directory<\/span><\/strong><\/p>\n
By default \u2018useradd\u2018 command creates a user\u2019s home directory under \/home directory with username. Thus, for example, we\u2019ve seen above the default home directory for the user \u2018hydhost\u2018 is \u2018\/home\/hydhost\u2018.<\/span><\/p>\n
However, this action can be changed by using \u2018-d\u2018 option along with the location of new home directory (i.e. \/data\/projects). For example, the following command will create a user \u2018project1\u2018 with a home directory \u2018\/data\/projects\u2018.<\/span><\/p>\n
useradd -d \/data\/projects project<\/p>\n
3. Create a User with Specific User ID<\/span><\/strong><\/p>\n
In Linux, every user has its own UID (Unique Identification Number). By default, whenever we create a new user accounts in Linux, it assigns userid 500, 501, 502 and so on\u2026<\/span><\/p>\n
But, we can create user\u2019s with custom userid with \u2018-u\u2018 option. For example, the following command will create a user \u2018navin\u2018 with custom userid \u2018999\u2018.<\/span><\/p>\n
\"\"<\/a><\/p>\n
 <\/p>\n
4. Create a User with Specific Group ID<\/span><\/p>\n
Similarly, every user has its own GID (Group Identification Number). We can create users with specific group ID\u2019s as well with -g option.<\/span><\/p>\n
Here in this example, we will add a user \u2018manoj\u2018 with a specific UID and GID simultaneously with the help of \u2018-u\u2018 and \u2018-g\u2018 options.<\/span><\/p>\n
\"\"<\/a><\/p>\n
5. Add a User to Multiple Groups<\/span><\/p>\n
The \u2018-G\u2018 option is used to add a user to additional groups. Each group name is separated by a comma, with no intervening spaces.<\/span><\/p>\n
Here in this example, we are adding a user \u2018manoj<\/span>\u2018 into multiple groups like admins, webadmin and developer.<\/span><\/p>\n
\"\"<\/a><\/p>\n
Next, verify that the multiple groups assigned to the user with id command.<\/span><\/p>\n
6. Add a User without Home Directory<\/span><\/p>\n
In some situations, where we don\u2019t want to assign a home directories for a user\u2019s, due to some security reasons. In such situation, when a user logs into a system that has just restarted, its home directory will be root. When such user uses su command, its login directory will be the previous user home directory.<\/span><\/p>\n
To create user\u2019s without their home directories, \u2018-M\u2018 is used. For example, the following command will create a user \u2018hydhost1\u2018 without a home directory.<\/span><\/p>\n
\"\"<\/a><\/p>\n
Now, let\u2019s verify that the user is created without home directory, using ls command.<\/span><\/p>\n
7. Create a User with Account Expiry Date<\/span><\/p>\n
By default, when we add user\u2019s with \u2018useradd\u2018 command user account never get expires i.e their expiry date is set to 0 (means never expired).<\/span><\/p>\n
However, we can set the expiry date using \u2018-e\u2018 option, that sets date in YYYY-MM-DD format. This is helpful for creating temporary accounts for a specific period of time.<\/span><\/p>\n
Here in this example, we create a user \u2018aparna\u2018 with account expiry date i.e. 27th April 2014 in YYYY-MM-DD format.<\/span><\/p>\n
\"\"<\/a><\/p>\n
Next, verify the age of account and password with \u2018chage\u2018 command for user \u2018aparna\u2018 after setting account expiry date.<\/span><\/p>\n
8. Create a User with Password Expiry Date<\/span><\/p>\n
The \u2018-f\u2018 argument is used to define the number of days after a password expires. A value of 0 inactive the user account as soon as the password has expired. By default, the password expiry value set to -1 means never expire.<\/span><\/p>\n
Here in this example, we will set a account password expiry date i.e. 45 days on a user \u2018tecmint\u2019 using \u2018-e\u2018 and \u2018-f\u2018 options.<\/span><\/p>\n
\"\"<\/a><\/p>\n
9. Add a User with Custom Comments<\/span><\/p>\n
The \u2018-c\u2018 option allows you to add custom comments, such as user\u2019s full name, phone number, etc to \/etc\/passwd file. The comment can be added as a single line without any spaces.<\/span><\/p>\n
For example, the following command will add a user \u2018mansi\u2018 and would insert that user\u2019s full name, Manis Khurana, into the comment field.<\/span><\/p>\n
\"\"<\/a><\/p>\n
You can see your comments in \u2018\/etc\/passwd\u2018 file in comments section<\/span><\/p>\n
10. Change User Login Shell:<\/span><\/p>\n
Sometimes, we add users which has nothing to do with login shell or sometimes we require to assign different shells to our users. We can assign different login shells to a each user with \u2018-s\u2018 option.<\/span><\/p>\n
\"\"<\/a><\/p>\n
Here in this example, will add a user \u2018tecmint\u2018 without login shell i.e. \u2018\/sbin\/nologin\u2018 shell.<\/span><\/p>\n
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The Complete Guide to \u201cuseradd\u201d Command in Linux We all are aware about the most popular command called \u2018useradd\u2018 or \u2018adduser\u2018 in Linux. There are times when a Linux System Administrator asked to create user accounts on Linux with some specific properties, limitations or comments. In Linux, a \u2018useradd\u2018 command is a low-level utility that\u2026 Read More »<\/a><\/span><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_eb_attr":"","footnotes":""},"categories":[6],"tags":[],"class_list":["post-664","post","type-post","status-publish","format-standard","hentry","category-vps"],"_links":{"self":[{"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/posts\/664","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/comments?post=664"}],"version-history":[{"count":3,"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/posts\/664\/revisions"}],"predecessor-version":[{"id":678,"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/posts\/664\/revisions\/678"}],"wp:attachment":[{"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/media?parent=664"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/categories?post=664"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/hyderabadwebhosting.in\/blog\/wp-json\/wp\/v2\/tags?post=664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}