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grep meaning

 
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# 1  
Old 03-06-2011
grep meaning
Hi Guys, Im trying to understand the below command. can anybody help me out please?
Code:
grep "^[1-9][0-9][0-9][0-9]" ./messi

thanks.
# 2  
Old 03-06-2011
It returns any line which starts (^) with four consecutive numbers ([0-9][0-....]) in file messi which is in your current directory (.) (that is, ./messi).

As this isn't an HP-UX-specific question, I will move it to the scripting sub-forum.
This User Gave Thanks to Scott For This Post:
messi777
# 3  
Old 03-06-2011
Thanks and sorry for the wrong place to post.

but what do you mean by consecutive numbers ([0-9][0-....])? can you give me some examples please?
# 4  
Old 03-06-2011
Consecutive means one that follows another.

I was too lazy to type
Code:
[1-9][0-9][0-9][0-9]

so I typed
Code:
[1-9][0....]

Seeing that, I correct myself.

Your code:
Code:
^[1-9][0-9][0-9][0-9]

means any line starting with a number between 1 and 9, followed by three numbers between 0 and 9.
# 5  
Old 03-06-2011
Why then I write this:
Code:
grep "^[1-9][0-9][0-9]" ./messi

I also get this in below?

1054.0|3781915734.0|
# 6  
Old 03-06-2011
Because you said you wanted to find three numbers.

It found three numbers. Nothing is said about what comes after the three numbers.

If you want to find only three numbers, use:

Code:
grep "^[1-9][0-9][0-9][^0-9]

The caret in red means not a number.
# 7  
Old 03-06-2011
thanks a lot!
 
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