WebNov 18, 2024 · This means that the whole regular expression also matches the empty string. The [Y] is identical to just Y. Had you used [Yy], it would have match an upper or lower-case y character. In this case, since you use /i to get case-insensitivity, it's enough with /^Y$/i. The same thing goes for the N test, use either /^N$/i or /^ [Nn]$/. WebJun 18, 2024 · You are checking if $dir is non-empty, so opposite of what you are trying to achieve. Use -z (or !-s) instead. Also, each $dir is just the filename without the path, so you …
Check If a Variable is NULL - Perl - Tek-Tips
WebIdiom #110 Check if string is blank. Set the boolean blank to true if the string s is empty, or null, or contains only whitespace ; false otherwise. WebJun 26, 2015 · As mentioned in the answer on SO, here is a way to check: if [ -z $ {somevar+x} ]; then echo "somevar is unset"; else echo "somevar is set to '$somevar'"; fi where $ {somevar+x} is a parameter expansion which evaluates to the null if var is unset and substitutes the string "x" otherwise. porsche 936 turbo images
How to check if 2 files are empty in perl using if condition
By empty, the OP probably means empty string, not false. The standard way to check that is length in Perl. Also, do not use $a and $b as they are package variables used by sort. – Sinan Ünür Nov 10, 2010 at 15:16 @Sinan: The OP declares $a and $b with my. These are not package variables. Thanks for the good point though. – Eugene Yarmash WebJan 31, 2013 · Perl provides two usable default values instead of undef. If you use a variable that is undef in a numerical operation, it pretends to be 0. If you use it in a string … WebNov 16, 2013 · if ($str eq '') { print "String is empty."; } That would work, but if use warnings; is in effect, as it should be, then you might get a Use of uninitialized value warnings if $str … porsche 930 turbo suspension