--help

display this help and exit

--version

output version information and exitPrint the value of EXPRESSION to standard output. A blank line below separates increasing precedence groups. EXPRESSION may be:ARG1 | ARG2ARG1 if it is neither null nor 0, otherwise ARG2ARG1 & ARG2ARG1 if neither argument is null or 0, otherwise 0ARG1 < ARG2ARG1 is less than ARG2ARG1 <= ARG2ARG1 is less than or equal to ARG2ARG1 = ARG2ARG1 is equal to ARG2ARG1 != ARG2ARG1 is unequal to ARG2ARG1 >= ARG2ARG1 is greater than or equal to ARG2ARG1 > ARG2ARG1 is greater than ARG2ARG1 + ARG2arithmetic sum of ARG1 and ARG2ARG1 - ARG2arithmetic difference of ARG1 and ARG2ARG1 * ARG2arithmetic product of ARG1 and ARG2ARG1 / ARG2arithmetic quotient of ARG1 divided by ARG2ARG1 % ARG2arithmetic remainder of ARG1 divided by ARG2STRING : REGEXPanchored pattern match of REGEXP in STRINGmatch STRING REGEXPsame as STRING : REGEXPsubstr STRING POS LENGTHsubstring of STRING, POS counted from 1index STRING CHARSindex in STRING where any CHARS is found, or 0length STRINGlength of STRING+ TOKENinterpret TOKEN as a string, even if it is akeyword like 'match' or an operator like '/'( EXPRESSION )value of EXPRESSIONBeware that many operators need to be escaped or quoted for shells. Comparisons are arithmetic if both ARGs are numbers, else lexi‐cographical. Pattern matches return the string matched between \( and \) or null; if \( and \) are not used, they return the numberof 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 3if an error occurred.AUTHORWritten by Mike Parker, James Youngman, and Paul Eggert.REPORTING BUGSGNU coreutils online help: <http://www.gnu.org/software/coreutils/>Report expr translation bugs to <http://translationproject.org/team/>COPYRIGHTCopyright © 2017 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.