NAME

       expr - Print the value of `EXPRESSION` to standard output

SYNOPSIS

       expr [--version] [--help] [expression]

DESCRIPTION

       Print the value of `EXPRESSION` to standard output

OPTIONS

       --version
              output version information and exit

       --help display this help and exit

       [expression]

EXTRA

       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.

       Environment variables:

       -  EXPR_DEBUG_TOKENS=1:  dump  expression's  tokens  -  EXPR_DEBUG_RPN=1:  dump expression
       represented in reverse polish notation - EXPR_DEBUG_SYA_STEP=1: dump each  parser  step  -
       EXPR_DEBUG_AST=1: dump expression represented abstract syntax tree

VERSION

       v0.0.20

                                           expr 0.0.20                                    expr(1)