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|on Aug 24, 1999 at 22:41 UTC||Need Help??|
See the current Perl documentation for substr.
Here is our local, out-dated (pre-5.6) version:
substr - get or alter a portion of a stirng
Extracts a substring out of
EXPR and returns it. First character is at offset
If you specify a substring that is partly outside the string, the part within the string is returned. If the substring is totally outside the string a warning is produced.
You can use the substr() function as an lvalue, in which case EXPR must be an lvalue. If you assign something shorter than LEN, the string will shrink, and if you assign something longer than LEN, the string will grow to accommodate it. To keep the string the same length you may need to pad or chop your value using sprintf().
An alternative to using substr() as an lvalue is to specify the replacement string as the 4th argument. This allows you to replace parts of the EXPR and return what was there before in one operation.