.TH ENVIRON 5.SH NAMEenviron \- user environment.SH SYNOPSIS.B extern char **environ;.SH DESCRIPTIONAn array of strings called the `environment' ismade available by.IR exec (2)when a process begins.By convention these strings have the form`name=value'.The following names are used by various commands:.TPPATHThe sequence of directory prefixes that.I sh, time,.IR nice (1),etc.,apply in searching for a file known by an incomplete path name.The prefixes are separated by `:'..IR Login (1)sets PATH=:/bin:/usr/bin..TPHOMEA user's login directory, set by.IR login (1)from the password file.IR passwd (5)..TPTERMThe kind of terminal for which output is to be prepared.This information is used by commands, such as.I nroffor.IR plot (1),which may exploit special terminal capabilities.See.IR term (7)for a list of terminal types..PPFurther names may be placed in the environment bythe.I exportcommand and `name=value' arguments in.IR sh (1),or by .IR exec (2).It is unwise to conflict withcertain Shell variables that are frequently exported by`.profile' files:MAIL, PS1, PS2, IFS..SH SEE ALSOexec(2), sh(1), term(7), login(1)