HP-UX Reference (11i v1 05/09) - 1 User Commands N-Z (vol 2)

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sh-posix(1) sh-posix(1)
A variable can be typed as an integer with the
-i option of the typeset special command, as in
typeset -i
[base] name. Arithmetic evaluation is performed on the value of each assignment to a vari-
able with the
-i attribute. If you do not specify an arithmetic base, the first assignment to the variable
determines the arithmetic base. This base is used when parameter substitution occurs.
Since many of the arithmetic operators require quoting, an alternative form of the
let command is pro-
vided. For any command beginning with
((, all characters until the matching )) are treated as a quoted
expression. More precisely,
((...)) is equivalent to
let "...".
Arithmetic expressions given with
let command, ((...
)), and $((...)) will be processed according to
ISOC standard with the exception of
++,
--, ?:, and , operators. Integer constants beginning with 0 and
0x (or 0X) will be recognised as octal and hexadecimal numbers by these evaluators only if environment
variable UNIX95 is defined.
Prompting
When used interactively, the shell prompts with the value of
PS1 before reading a command. Whenever a
newline is received and further input is needed to complete a command, the secondary prompt (the value of
PS2) is issued.
Conditional Expressions
A conditional expression is used with the [[ compound command to test attributes of files and to com-
pare strings. Word splitting and file name generation are not performed on the words between
[[ and ]].
Each expression can be constructed from one or more of the following unary or binary expressions:
-a file True, if file exists.
-b file True, if file exists and is a block special file.
-c file True, if file exists and is a character special file.
-d file True, if file exists and is a directory.
-e file True, if file exists.
-f file True, if file exists and is an ordinary file.
-g file True, if file exists and has its setgid bit set.
-h file True, if file exists and is a symbolic link.
-k file True, if file exists and has its sticky bit set.
-n string True, if length of string is nonzero.
-o option True, if the set option named option is on.
-p file True, if file exists and is a fifo special file or a pipe.
-r file True, if file exists and is readable by current process.
-s file True, if file exists and has a size greater than zero.
-t fildes True, if file descriptor number fildes is open and is associated with a terminal
device.
-u file True, if file exists and has its setuid bit set.
-w file True, if file exists and is writable by the current process.
-x file True, if file exists and is executable by the current process. If file exists and is a
directory, then the current process has permission to search in the directory.
-z string True, if length of string is zero.
-L file True, if file exists and is a symbolic link.
-O file True, if file exists and is owned by the effective user ID of this process.
-G file True, if file exists and its group matches the effective group ID of this process.
-S file True, if file exists and is a socket.
file1 -nt file2 True, if file1 exists and is newer than file2.
file1 -ot file2 True, if file1 exists and is older than file2.
file1 -ef file2 True, if file1 and file2 exist and refer to the same file.
string = pattern True, if string matches pattern.
string != pattern True, if string does not match pattern.
string < string2 True, if string1 comes before string2 based on the ASCII value of their charac-
ters.
string > string2 True, if string1 comes after string2 based on the ASCII value of their characters.
exp1 -eq exp2 True, if exp1 is equal to exp2.
exp1 -ne exp2 True, if exp1 is not equal to exp2.
exp1 -lt exp2 True, if exp1 is less than exp2.
exp1 -gt exp2 True, if exp1 is greater than exp2.
exp1 -le exp2 True, if exp1 is less than or equal to exp2.
exp1 -ge exp2 True, if exp1 is greater than or equal to exp2.
Section 1−−908 Hewlett-Packard Company − 17 − HP-UX 11i Version 1: September 2005