su(1) — Commands
OSF
NAME
su − Substitutes user ID temporarily
SYNOPSIS
su [-f] | [-] [user]
The su command demands the password of the specified user, and if it is given, changes to that user and invokes the shell (sh or csh) without changing the current directory.
FLAGS
-fPrevents csh from executing the .cshrc file, thus making su start up faster.
−Simulates a full login.
DESCRIPTION
The user environment is unchanged except for HOME and SHELL, which are taken from the password file for the user being substituted (see environ). The new user ID stays in force until the shell exits.
If no user is specified, root is assumed. Only users who belong to group number 0 (zero) can issue su to become root, even with the root password. To remind superusers of their responsibilities, the shell substitutes a # (number sign) for its usual prompt.