User and Groups Administration

Common uses

• I. User and groups basics
  • A. Adding a new user
  • B. Set a password
  • C. Password with stdin
  • D. Create a new group
  • E. Add an user into a group
  • F. Review the groups of an user
• II. Change
• III. Locking Accounts
• IV. Deleting Users
• Reference

I. User and groups basics

A. Adding a new user

#!/bin/sh

# Basic usage useradd:
# $ useradd [-q] [-b bits] [-t dsa | ecdsa | ed25519 | rsa | rsa1] [-N new_passphrase] [-C comment] [-f output_keyfile]
# -q : Quiet
# The
# (-b 521 is the biggest value posible for ecdsa)

useradd juan

B. Set a password

#!/bin/sh

# Basic usage passwd:
# $  passwd [-f] [-n] [-i [identity_file]] [-p port] [-o ssh_option] [user@]hostname
# -f: Forced mode, read more.
# -n: Do a dry-run. Print the keys that would have been installed

passwd juan

C. Password with stdin

#!/bin/sh

# Basic usage passwd:
# $  passwd [-f] [-n] [-i [identity_file]] [-p port] [-o ssh_option] [user@]hostname
# -f: Forced mode, read more.
# -n: Do a dry-run. Print the keys that would have been installed

passwd juan

D. Create a new group

#!/bin/sh

# Basic usage groupadd:
# $  groupadd [-f] [-n] [-i [identity_file]] [-p port] [-o ssh_option] [user@]hostname
# -f: Forced mode, read more.
# -n: Do a dry-run. Print the keys that would have been installed

groupadd familia

E. Add an user into a group

#!/bin/sh

# Basic usage usermod:
# $  usermod [-f] [-n] [-i [identity_file]] [-p port] [-o ssh_option] [user@]hostname
# -f: Forced mode, read more.
# -n: Do a dry-run. Print the keys that would have been installed

usermod -aG familia juan

F. Review the groups of an user

#!/bin/sh

# Basic usage groups:
# $  groups [-f] [-n] [-i [identity_file]] [-p port] [-o ssh_option] [user@]hostname
# -f: Forced mode, read more.
# -n: Do a dry-run. Print the keys that would have been installed

groups juan

II. Chage

chage -l juan

III. Locking Accounts

# Bring a folder from other machine
scp -r user@remote-ip-address:/home/other-user/Videos/testSCP/ Documents/

IV. Deleting Users

Example of SSH Tunneling and port forwarding

Reference

https://www.youtube.com/watch?v=z2DSNLJsdSw&list=PLXJyD2dL4oqeX-C3MvsMUJuEzWM4vLK2C

Credits

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