svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
expr(1)
expr(1) User Commands expr(1)
NAME
expr - evaluate arguments as an expression
SYNOPSIS
/usr/bin/expr argument...
/usr/xpg4/bin/expr argument...
/usr/xpg6/bin/expr argument...
DESCRIPTION
/usr/bin/expr, /usr/xpg4/bin/expr
The expr utility evaluates the expression and writes the result to
standard output. The character 0 is written to indicate a zero value
and nothing is written to indicate a null string.
/usr/xpg6/bin/expr
The expr utility evaluates the expression and writes the result to
standard output followed by a NEWLINE. If there is no result from expr
processing, a NEWLINE is written to standard output.
OPERANDS
The argument operand is evaluated as an expression. Terms of the ex‐
pression must be separated by blanks. Characters special to the shell
must be escaped (see sh(1)). Strings containing blanks or other special
characters should be quoted. The length of the expression is limited to
LINE_MAX (2048 characters).
The operators and keywords are listed below. The list is in order of
increasing precedence, with equal precedence operators grouped within
{} symbols. All of the operators are left-associative.
expr | expr
Returns the evaluation of the first expr if it is neither NULL nor
0; otherwise, returns the evaluation of the second expr if it is
not NULL; otherwise, 0.
expr & expr
Returns the first expr if neither expr is NULL or 0, otherwise re‐
turns 0.
expr { =, >, >=, <, <=, != } expr
Returns the result of an integer comparison if both arguments are
integers, otherwise returns the result of a string comparison using
the locale-specific coalition sequence. The result of each compari‐
son is 1 if the specified relationship is TRUE, 0 if the relation‐
ship is FALSE.
expr { +, − } expr
Addition or subtraction of integer-valued arguments.
expr { *, /, % } expr
Multiplication, division, or remainder of the integer-valued argu‐
ments.
expr : expr
The matching operator : (colon) compares the first argument with
the second argument, which must be an internationalized basic regu‐
lar expression (BRE), except that all patterns are anchored to the
beginning of the string. That is, only sequences starting at the
first character of a string are matched by the regular expression.
See regex(7) and NOTES. Normally, the /usr/bin/expr matching opera‐
tor returns the number of bytes matched and the /usr/xpg4/bin/expr
and /usr/xpg6/bin/expr matching operator returns the number of
characters matched (0 on failure). If the second argument contains
at least one BRE sub-expression [\(...\)], the matching operator
returns the string corresponding to \1.
integer
An argument consisting only of an (optional) unary minus followed
by digits.
string
A string argument that cannot be identified as an integer argument
or as one of the expression operator symbols.
The following four operators: index, length, match, and substr, are all
at the same precedence:
index string character-list
Report the first byte in string (counting from one) where a byte
from character-list matches a byte from string. If no bytes in
character-list appear in string, a 0 is returned.
length string
Return the length (that is, the number of bytes) of string. The
terminating nul character is not included in that count.
match string regular-expression
Synonymous with the expr : expr matching operator.
substr string integer-1 integer-2
Extract the sequence of bytes from string (counting from one)
starting at position integer-1 and of length integer-2 bytes. If
integer-1 has a value greater than the number of bytes in string,
expr returns a null string. If you try to extract more bytes than
there are in string, expr returns all the remaining bytes from
string. Results are unspecified if either integer-1 or integer-2 is
a negative value.
EXAMPLES
Example 1 Adding an integer to a shell variable
Add 1 to the shell variable a:
example$ a=`expr $a + 1`
Example 2 Returning a path name segment
The following example emulates basename(1), returning the last segment
of the path name $a. For $a equal to either /usr/abc/file or just file,
the example returns file. (Watch out for / alone as an argument: expr
takes it as the division operator. See NOTES below.)
example$ expr $a : '.*/\(.*\)' \| $a
Example 3 Using // characters to simplify the expression
Here is a better version of the previous example. The addition of the
// characters eliminates any ambiguity about the division operator and
simplifies the whole expression.
example$ expr //$a : '.*/\(.*\)'
/usr/bin/expr
Example 4 Returning the number of bytes in a variable
example$ expr "$VAR" : '.*'
/usr/xpg4/bin/expr
Example 5 Returning the number of characters in a variable
example$ expr "$VAR" : '.*'
ENVIRONMENT VARIABLES
See environ(7) for descriptions of the following environment variables
that affect the execution of expr: LANG, LC_ALL, LC_COLLATE, LC_CTYPE,
LC_MESSAGES, and NLSPATH.
EXIT STATUS
As a side effect of expression evaluation, expr returns one of the fol‐
lowing exit values if no error occurred:
0 If the expression is neither NULL nor 0.
1 If the expression is either NULL or 0.
If an error occurred, expr returns:
2 For invalid expressions.
> 2 An error other than an invalid expression occurred.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
tab() box; cw(2.75i) |cw(2.75i) lw(2.75i) |lw(2.75i) ATTRIBUTE TYPEAT‐
TRIBUTE VALUE _ Availabilitysystem/core-os _ CSIEnabled. See Notes. _
Interface StabilitySee below. _ StandardSee standards(7).
The match, substr, length, and index operators are Uncommitted. Every‐
thing else is Committed.
SEE ALSO
basename(1), echo(1), ed(1), sh(1), Intro(3), attributes(7), envi‐
ron(7), regex(7), standards(7)
DIAGNOSTICS
syntax error Operator and operand errors.
non-numeric argument Arithmetic is attempted on such a string.
NOTES
Operators Not CSI-Enabled
The following three operators are not CSI enabled. They are also not
available in /usr/xpg4/bin/expr and /usr/xpg6/bin/expr:
index string character-list
length string
substr string integer-1 integer-2
After argument processing by the shell, expr cannot tell the difference
between an operator and an operand except by the value. If $a is an =,
the command:
example$ expr $a = '='
looks like:
example$ expr = = =
as the arguments are passed to expr (and they are all taken as the =
operator). The following works:
example$ expr X$a = X=
Regular Expressions
Unlike some previous versions, expr uses Internationalized Basic Regu‐
lar Expressions for all system-provided locales. Internationalized Reg‐
ular Expressions are explained on the regex(7) manual page.
Operator Precedence Order in Other Versions
In previous releases of Solaris, there was a /usr/ucb/expr command that
had a different operator precedence order than the expr command de‐
scribed here. Also, the /usr/gnu/bin/expr command has its own unique
operator precedence order.
Oracle Solaris 11.4 29 Nov 2022 expr(1)