Open System Services Shell and Utilities Reference Manual (G06.27+, H06.04+)

User Commands (k - l) ksh(1)
PATH The search path for commands. (See Execution.) You cannot change PATH if execut-
ing under rsh, except in .profile.
PS1 The value of this parameter is expanded for parameter substitution to define the pri-
mary prompt string which by default is the $ (dollar sign). The ! (exclamation point) in
the primary prompt string is replaced by the command number. (See Command Reen-
try.)
PS2 Secondary prompt string, by default > (right angle bracket).
PS3 Selection prompt string used within a select loop, by default #? (number sign, question
mark).
PS4 The value of this parameter is expanded for parameter substitution and precedes each
line of an execution trace. If omitted, the execution trace prompt is + (plus sign).
SHELL The pathname of the shell is kept in the environment.
TMOUT
If set to a value greater than 0 (zero), the shell terminates if a command is not entered
within the prescribed number of seconds after issuing the PS1 prompt. (Note that the
shell can be compiled with a maximum bound for this value that cannot be exceeded.)
TZ Current value for the time zone, if any.
VISUAL
If the value of this variable ends in vi, the corresponding option (see the set command
in Special sh Commands) will be turned on.
The shell gives default values to PATH, PS1, PS2, TMOUT, and IFS, while HOME, SHELL,
and ENV are not set by the shell.
Interpretation of Spaces
After parameter and command substitution, the results of substitutions are scanned for the field
separator characters (those found in IFS), and split into distinct arguments where such characters
are found. Explicit null arguments (‘‘ or ’’) are retained. Implicit null arguments (those resulting
from parameters that have no values) are removed.
Filename Generation
Following substitution, each command word is scanned for the characters * (asterisk), ? (ques-
tion mark), and [](brackets), unless the -f option was set. If one of these characters appears, the
word is regarded as a pattern. The word is replaced with lexicographically sorted filenames that
match the pattern. If no filename is found that matches the pattern, the word is left unchanged.
When a pattern is used for filename generation, the . (dot) character at the start of a filename or
immediately following a / (slash), as well as the / character itself, must be matched explicitly. In
other instances of pattern matching, the / and . are not treated specially.
* Matches any string, including the null string.
? Matches any single character.
[...] Matches any one of the enclosed characters. In an expression such as [a-z], the -
(dash) means "through" according to the current collating sequence. The collating
sequence is determined by the value of the LC_COLLATE environment variable. If
the first character following the [ (left bracket) is a ! (exclamation point), then any
character not enclosed is matched. A - can be included in the character set by putting it
as the first or last character.
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