Environment variables are a variable key pair stored in the shell's environment space. Here is a list of common environment variables:
| Variable |
Description |
| HISTFILE |
The name of the file in which command history is saved |
| HISTFILESIZE |
The maximum number of lines contained in the history file |
| HOSTNAME |
The system's host name |
| LD_LIBRARY_PATH |
It is a colon-separated set of directories where libraries should be searched for |
| PS1 |
Your default (first) shell prompt |
| USER |
Current logged in user's name. |
| PATH |
Colon separated list of directories to search for binaries. |
| DISPLAY |
Network name of the X11 display to connect to, if available. |
| SHELL |
The current shell. |
| TERM |
The name of the user's terminal. Used to determine the capabilities of the terminal. |
| TERMCAP |
Database entry of the terminal escape codes to perform various terminal functions. |
| OSTYPE |
Type of operating system. |
| MACHTYPE |
The CPU architecture that the system is running on. |
| EDITOR |
The user's preferred text editor. |
| PAGER |
The user's preferred text pager. |
| MANPATH |
Colon separated list of directories to search for manual pages. |
