Hello all,
I read somewher that regular expressions work with ASCII table so when i type
it uses values from ACII dec97(a) to dec122(z), right ?
But if I have file containing diacritics, lets say (ordinary Slovak language characters):
Why this regexp know diacritics? And why know only lower case and not "ž" ??? This is strange for me. Friend told me it could be something with $LANG. So my $LANG is:
Also I would ask if I want uppercase file with diacritic i type:
why it not change lower to upper ?
Thanks a lot for reply
PS: I hope that characters display properly

maybe i know why is "ž" different it is "behind" z so regex [a-z] did not match the "ž" but still many thinngs are unclear

If you want uppercase as well you have to specify

What you are discusiing is called a collating sequence. Do a web search for "POSIX collating sequence" for further information.

To be language-neutral, your example would be written as
or if you only want lowercase characters

grep "[a-z][a-z]*" file_name

marek@cepi:~$ cat diakritika 
áôúéťľúľščťžýáíéôäúú
ÁôúÉŤĽÚĽŠČŤŽÝÁÍÉôäÚÚ

marek@cepi:~$ grep -o "[a-z][a-z]*" diakritika 
áôúéťľúľščť
ýáíéôäúú
ôú
ôä

marek@cepi:~$ echo $LANG
en_US.UTF-8

marek@cepi:~$ cat diakritika | tr "[:lower:]" "[:upper:]"
áôúéťľúľščťžýáíéôäúú
ÁôúÉŤĽÚĽŠČŤŽÝÁÍÉôäÚÚ

Thank you for reply. Is there an option how to convert lowercase diacritics to uppercase ?