EXPR("1") manual page
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expr - evaluate expressions
expr EXPRESSION
expr OPTION
- --help
- display this help and exit
- --version
- output
version information and exit
Print the value of EXPRESSION to standard
output. A blank line below separates increasing precedence groups. EXPRESSION
may be:
- ARG1 | ARG2
- ARG1 if it is neither null nor 0, otherwise ARG2
- ARG1
& ARG2
- ARG1 if neither argument is null or 0, otherwise 0
- ARG1 < ARG2
- ARG1
is less than ARG2
- ARG1 <= ARG2
- ARG1 is less than or equal to ARG2
- ARG1 =
ARG2
- ARG1 is equal to ARG2
- ARG1 != ARG2
- ARG1 is unequal to ARG2
- ARG1 >=
ARG2
- ARG1 is greater than or equal to ARG2
- ARG1 > ARG2
- ARG1 is greater than
ARG2
- ARG1 + ARG2
- arithmetic sum of ARG1 and ARG2
- ARG1 - ARG2
- arithmetic
difference of ARG1 and ARG2
- ARG1 * ARG2
- arithmetic product of ARG1 and
ARG2
- ARG1 / ARG2
- arithmetic quotient of ARG1 divided by ARG2
- ARG1 % ARG2
- arithmetic remainder of ARG1 divided by ARG2
- STRING : REGEXP
- anchored pattern
match of REGEXP in STRING
- match STRING REGEXP
- same as STRING : REGEXP
- substr
STRING POS LENGTH
- substring of STRING, POS counted from 1
- index STRING
CHARS
- index in STRING where any CHARS is found, or 0
- length STRING
- length
of STRING
- + TOKEN
- interpret TOKEN as a string, even if it is a
- keyword
like ‘match’ or an operator like ‘/’
- ( EXPRESSION )
- value of EXPRESSION
Beware
that many operators need to be escaped or quoted for shells. Comparisons
are arithmetic if both ARGs are numbers, else lexicographical. Pattern matches
return the string matched between \( and \) or null; if \( and \) are not used,
they return the number of characters matched or 0.
Exit status is 0 if EXPRESSION
is neither null nor 0, 1 if EXPRESSION is null or 0, 2 if EXPRESSION is
syntactically invalid, and 3 if an error occurred.
Written by Mike
Parker.
Report bugs to <bug-coreutils@gnu.org>.
Copyright
© 2008 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or
later <http://gnu.org/licenses/gpl.html
>
This is free software: you are free to change and redistribute it. There
is NO WARRANTY, to the extent permitted by law.
The full documentation
for expr is maintained as a Texinfo manual. If the info and expr programs
are properly installed at your site, the command
- info coreutils ’expr invocation’
should give you access to the complete manual.
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