Problem with upper and lowercase in awk

Shell Programming and Scripting
1

My awk (GNU Awk 3.1.8 on Ubuntu 12.04) seems to ignore case.

cat file
abc
ABC
aBc
123

awk '/[a-z]/&&/[A-Z]/{print $0,"[PASS]";next}{print $0,"[FAIL]"}' file

My result:

abc [PASS]
ABC [PASS]
aBc [PASS]
123 [FAIL]

Correct result:

abc [FAIL]
ABC [FAIL]
aBc [PASS]
123 [FAIL]

Other example

cat d
a
b
C
D

awk '/[A-Z]/' d
b
C
D
1 Like
2

Interesting. gawk 3.1.5 does the same thing.

3

Ahh, good I am not alone with this :slight_smile:
Some other strange test

echo a | awk '/[A-Z]/'
<no output>

echo b | awk '/[A-Z]/'
b

echo aa | awk '/[A-Z]/'
<no output>

echo ab | awk '/[A-Z]/'
ab

Single small a seems to work, but nothing else, strange

4

This is probably a locale issue. Try:

echo b | awk '/[[:upper:]]/'
5

Thanks
[[:upper:]] [[:lower:]] seems to work correct.
But so should A-Z and a-z do also

6

It has to do with locales as Scrutinizer mentioned:

Ranges and Locales - The GNU Awk User's Guide

1 Like
7

Uff, this tells me that I have to take care when handling upper/lower case issue.
Thanks