z/OS V1R9.0 UNIX System Services Command ... - Christian Grothoff

Assigning a value to name, and the behavior given for calling export with
arguments are extensions of the POSIX standard.
Related Information
cd, date, set, sh, typeset, vi
expr — Evaluate arguments as an expression
Format
Description
expr –W expression
The set of arguments passed to expr constitutes an expression to be evaluated.
Each command argument is a separate token of the expression. expr writes the
result of the expression on the standard output. This command is primarily intended
for arithmetic and string manipulation on shell variables.
expr supports the following operators. Operators explained together have equal
precedence; otherwise, they are in increasing order of precedence. expr stores an
expression as a string and converts it to a number during the operation. If the
context requires a Boolean value, a numeric value of 0 (zero) or a null string ("") is
false, and any other value is true. Numbers have an optional leading sign. If the -W
option is not specified, numbers are decimal. If the -W option is specified,
expressions may contain octal, hexidecimal, or decimal numbers. expr determines
the base of the number as follows:
v Any number that starts with 0x is hex.
v Any number that starts with 0 is octal.
v Any number that does not start with 0x or 0 is decimal.
Numbers are manipulated as long integers.
expr1 | expr2
Results in the value expr1 if expr1 is true; otherwise, it results in the value
of expr2.
expr1 & expr2
Results in the value of expr1 if both expressions are true; otherwise, it
results in 0.
expr1 = expr2 |
expr1 > expr2
If both expr1 and expr2 are numeric, expr compares them as numbers;
otherwise, it compares them as strings. If the comparison is true, the
expression results in 1; otherwise, it results in 0.
expr1 + expr2 | expr1 – expr2
Performs addition or subtraction on the two expressions. If either
expression is not a number, expr exits with an error.
expr1 * expr2 | expr1 / expr2 | expr1 % expr2
Performs multiplication, division, or modulus on the two expressions. If
either expression is not a number, expr exits with an error.
export
expr1 : re | match expr1 re
matches the regular expression re against expr1 treated as a string. The
regular expression is the same as that accepted by ed, except that the
match is always anchored—that is, there is an implied leading ^. Therefore,
Chapter 2. Shell command descriptions 265