22. Environment Variables

COLUMNS

Number of columns on the terminal (overrides termcap entry).

HOME

Directory in which to look for .screenrc.

LINES

Number of lines on the terminal (overrides termcap entry).

LOCKPRG

Screen lock program.

NETHACKOPTIONS

Turns on nethack option.

PATH

Used for locating programs to run.

SCREENCAP

For customizing a terminal's TERMCAP value.

SCREENDIR

Alternate socket directory.

SCREENRC

Alternate user screenrc file.

SHELL

Default shell program for opening windows (default `/bin/sh').

STY

Alternate socket name. If screen is invoked, and the environment variable STY is set, then it creates only a window in the running screen session rather than starting a new session.

SYSSCREENRC

Alternate system screenrc file.

TERM

Terminal name.

TERMCAP

Terminal description.

WINDOW

Window number of a window (at creation time).