Neozeed: New page: EXPR(1) UNIX Programmer's Manual EXPR(1) == NAME == expr - evaluate arguments as an expression == SYNOPSIS == expr arg ... == DESCRIPTION == Th...

2009-10-26T14:05:10Z

New page: EXPR(1) UNIX Programmer's Manual EXPR(1) == NAME == expr - evaluate arguments as an expression == SYNOPSIS == expr arg ... == DESCRIPTION == Th...

New page

EXPR(1) UNIX Programmer's Manual EXPR(1)

== NAME ==
expr - evaluate arguments as an expression

== SYNOPSIS ==
expr arg ...

== DESCRIPTION ==
The arguments are taken as an expression. After evaluation,
the result is written on the standard output. Each token of
the expression is a separate argument.

The operators and keywords are listed below. The list is in
order of increasing precedence, with equal precedence opera-
tors grouped.

_e_x_p_r | _e_x_p_r
yields the first _e_x_p_r if it is neither null nor `0',
otherwise yields the second _e_x_p_r.

_e_x_p_r & _e_x_p_r
yields the first _e_x_p_r if neither _e_x_p_r is null or `0',
otherwise yields `0'.

_e_x_p_r _r_e_l_o_p _e_x_p_r
where _r_e_l_o_p _i_s _o_n_e _o_f < <= = != >= >, yields `1' if the
indicated comparison is true, `0' if false. The com-
parison is numeric if both _e_x_p_r are integers, otherwise
lexicographic.

_e_x_p_r + _e_x_p_r
_e_x_p_r - _e_x_p_r
addition or subtraction of the arguments.

_e_x_p_r * _e_x_p_r
_e_x_p_r / _e_x_p_r
_e_x_p_r % _e_x_p_r
multiplication, division, or remainder of the argu-
ments.

_e_x_p_r : _e_x_p_r
The matching operator compares the string first argu-
ment with the regular expression second argument; regu-
lar expression syntax is the same as that of _e_d(1).
The $...$ pattern symbols can be used to select a
portion of the first argument. Otherwise, the matching
operator yields the number of characters matched (`0'
on failure).

( _e_x_p_r )
parentheses for grouping.

Examples:

To add 1 to the Shell variable _a:

a=`expr $a + 1`

To find the filename part (least significant part) of the
pathname stored in variable _a, which may or may not contain
`/':

expr $a : '.*/$.*$' '|' $a

Note the quoted Shell metacharacters.

== SEE ALSO ==
[[32v 1m ed|ed(1)]], [[32v 1m sh|sh(1)]], [[32v 1m test|test(1)]]

== DIAGNOSTICS ==
_E_x_p_r returns the following exit codes:

0 if the expression is neither null nor `0',
1 if the expression is null or `0',
2 for invalid expressions.

[[Category:32v man section 1]]

32v 1m expr - Revision history

Neozeed: New page: EXPR(1) UNIX Programmer's Manual EXPR(1) == NAME == expr - evaluate arguments as an expression == SYNOPSIS == expr arg ... == DESCRIPTION == Th...