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Full Discussion: Perl REGEX
Top Forums Shell Programming and Scripting Perl REGEX Post 302251063 by evilfreakz on Saturday 25th of October 2008 01:38:51 AM
Old 10-25-2008
Perl REGEX

Hi,
Can anyone help me to find regular expression for the following in Perl?
"The string can only contain lower case letters (a-z) and no more than one of any letter."
For example: "table" is accepted, whether "dude" is not.
I have coded like this:

$str = "table";
if ($str =~ m/\b([a-z])[^\1]\b/) {
...
}

But it does not work Image. Any helps would be appreciated. Thanks.
 

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REGEX(3)						     Library Functions Manual							  REGEX(3)

NAME
re_comp, re_exec - regular expression handler SYNOPSIS
char *re_comp(s) char *s; re_exec(s) char *s; DESCRIPTION
Re_comp compiles a string into an internal form suitable for pattern matching. Re_exec checks the argument string against the last string passed to re_comp. Re_comp returns 0 if the string s was compiled successfully; otherwise a string containing an error message is returned. If re_comp is passed 0 or a null string, it returns without changing the currently compiled regular expression. Re_exec returns 1 if the string s matches the last compiled regular expression, 0 if the string s failed to match the last compiled regular expression, and -1 if the compiled regular expression was invalid (indicating an internal error). The strings passed to both re_comp and re_exec may have trailing or embedded newline characters; they are terminated by nulls. The regular expressions recognized are described in the manual entry for ed(1), given the above difference. SEE ALSO
ed(1), ex(1), egrep(1), fgrep(1), grep(1) DIAGNOSTICS
Re_exec returns -1 for an internal error. Re_comp returns one of the following strings if an error occurs: No previous regular expression, Regular expression too long, unmatched (, missing ], too many () pairs, unmatched ). 3rd Berkeley Distribution May 15, 1985 REGEX(3)
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