LinuxQuestions.org - [SOLVED] grep command for uppercase

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- - grep command for uppercase (https://www.linuxquestions.org/questions/linux-newbie-8/grep-command-for-uppercase-934954/)

Micky12345

03-17-2012 11:32 AM

grep command for uppercase

i wrote a command

Code:

grep '^[[:upper:]]' file1

I want to find lines of file1 which contains only capital letters , but when i execute above command

i got lines starting with capital letter but after that it may or maynot contain capital letters

contents of my file1 are

Code:

HELLO

hello

Hello

HEllO

HOW

IT shows output as
HELLO
Hello
HEllo
HOW

But its not what i am expecting i want only output as
HELLO
HOW

colucix

03-17-2012 11:38 AM

Your regular expression matches a single character at the beginning of each line. Instead, you need to match any number of upper-case characters till the end of the line (add the $ anchor):

Code:

grep '^[[:upper:]]*$' file1

Edit: the command above matches empty lines, as well. To match only lines containing at least one upper-case character, use the extended regular expression option and the + modifier:

Code:

grep -E '^[[:upper:]]+$' file1

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