# Users and Permissions Cheatsheet
## Create a user (called "ashley")
```
# useradd --create-home ashley
```
## Create a user in groups "users" and "dev"
```
# useradd --create-home --groups users dev ashley
```
## Create a user with the UID 1337
```
# useradd --create-home --uid 1337 ashley
```
## Create or change a user password
```
# passwd ashley
<enter password>
```
## Add user to a group ("coder")
```
# usermod --append --groups coder ashley
```
## Remove a user from a group ("coder")
```
# gpasswd --delete ashley coder
```
## Delete a user from the system
```
# userdel ashley
```
## Delete a user and all user data from the system
```
# userdel --remove ashley
```
## Show which users are currently logged in
```
# w
```
## Show login history
```
# last
```
## Set default permission of files to 644
```
# echo "umask 022" >> /etc/profile
```
## Set default permission of files to 664
```
# echo "umask 002" >> /etc/profile
```
## Change ownership of a file ("example.txt") to user ("ashley")
```
# chown ashley:users example.txt
```
## Give read permission to user, group, and others
```
# chmod ugo+r example.txt
```
## Give write permission to user and group
```
# chmod ug+w example.txt
```
## Remove write permission to a file for group members
```
# chmod g-w example.txt
```
## Make a file executable
```
# chmod +x example.txt
```
## Log in as a different user
```
# su - ashley
```
## Run a command ("ls") as a different user
```
# su - ashley --comand ls
```
