109 lines
3.3 KiB
Plaintext
109 lines
3.3 KiB
Plaintext
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EXPR(1) User Commands EXPR(1)
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NNAAMMEE
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expr - evaluate expressions
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SSYYNNOOPPSSIISS
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eexxpprr _E_X_P_R_E_S_S_I_O_N
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eexxpprr _O_P_T_I_O_N
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DDEESSCCRRIIPPTTIIOONN
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----hheellpp display this help and exit
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----vveerrssiioonn
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output version information and exit
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Print the value of EXPRESSION to standard output. A blank line below
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separates increasing precedence groups. EXPRESSION may be:
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ARG1 | ARG2
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ARG1 if it is neither null nor 0, otherwise ARG2
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ARG1 & ARG2
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ARG1 if neither argument is null or 0, otherwise 0
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ARG1 < ARG2
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ARG1 is less than ARG2
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ARG1 <= ARG2
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ARG1 is less than or equal to ARG2
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ARG1 = ARG2
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ARG1 is equal to ARG2
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ARG1 != ARG2
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ARG1 is unequal to ARG2
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ARG1 >= ARG2
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ARG1 is greater than or equal to ARG2
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ARG1 > ARG2
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ARG1 is greater than ARG2
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ARG1 + ARG2
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arithmetic sum of ARG1 and ARG2
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ARG1 - ARG2
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arithmetic difference of ARG1 and ARG2
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ARG1 * ARG2
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arithmetic product of ARG1 and ARG2
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ARG1 / ARG2
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arithmetic quotient of ARG1 divided by ARG2
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ARG1 % ARG2
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arithmetic remainder of ARG1 divided by ARG2
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STRING : REGEXP
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anchored pattern match of REGEXP in STRING
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match STRING REGEXP
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same as STRING : REGEXP
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substr STRING POS LENGTH
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substring of STRING, POS counted from 1
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index STRING CHARS
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index in STRING where any CHARS is found, or 0
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length STRING
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length of STRING
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+ TOKEN
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interpret TOKEN as a string, even if it is a
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keyword like 'match' or an operator like '/'
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( EXPRESSION )
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value of EXPRESSION
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Beware that many operators need to be escaped or quoted for shells.
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Comparisons are arithmetic if both ARGs are numbers, else lexicographi-
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cal. Pattern matches return the string matched between \( and \) or
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null; if \( and \) are not used, they return the number of characters
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matched or 0.
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Exit status is 0 if EXPRESSION is neither null nor 0, 1 if EXPRESSION
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is null or 0, 2 if EXPRESSION is syntactically invalid, and 3 if an
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error occurred.
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AAUUTTHHOORR
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Written by Mike Parker, James Youngman, and Paul Eggert.
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RREEPPOORRTTIINNGG BBUUGGSS
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GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
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Report expr translation bugs to <https://translationproject.org/team/>
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CCOOPPYYRRIIGGHHTT
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Copyright (C) 2017 Free Software Foundation, Inc. License GPLv3+: GNU
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GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
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This is free software: you are free to change and redistribute it.
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There is NO WARRANTY, to the extent permitted by law.
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SSEEEE AALLSSOO
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Full documentation at: <https://www.gnu.org/software/coreutils/expr>
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or available locally via: info '(coreutils) expr invocation'
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GNU coreutils 8.29 December 2017 EXPR(1)
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