From 1b355ebba68bdd567dd3961a18291dfd9532c2e8 Mon Sep 17 00:00:00 2001 From: Eric Andersen Date: Tue, 5 Sep 2000 17:37:48 +0000 Subject: Added expr, from Edward Betts , with some fixups and docs added by me. -Erik --- docs/busybox.pod | 41 ++++++++++++++++++++++++++++++++++++++++- 1 file changed, 40 insertions(+), 1 deletion(-) (limited to 'docs/busybox.pod') diff --git a/docs/busybox.pod b/docs/busybox.pod index accdaed23..3bedcefb7 100644 --- a/docs/busybox.pod +++ b/docs/busybox.pod @@ -497,6 +497,45 @@ Example: ------------------------------- +=item echo + + +Usage: expr EXPRESSION + +Prints the value of EXPRESSION to standard output. + +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 + quote 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. + +------------------------------- + =item false Returns an exit code of FALSE (1) @@ -2112,4 +2151,4 @@ Enrique Zanardi =cut -# $Id: busybox.pod,v 1.65 2000/09/01 16:12:57 andersen Exp $ +# $Id: busybox.pod,v 1.66 2000/09/05 17:37:48 andersen Exp $ -- cgit v1.2.3