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February 20th, 2008, 10:54 AM

corticus

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Help with 'cut'

Hi all,

First post, hope I'm in the right place..

I am trying to modify the following line of a shell:
LSTID=`echo $FN | cut -f1 -d' ' | awk -F\. '{print $1}'`
What I want to do is set LSTID to the value contained in the first field of a tab delimited file, $FN.

Thanks!

February 20th, 2008, 11:28 AM

L7Sqr

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$FN is the file name? If that is the case your echo will simply print the name and not the contents of the file.

Code:

$ echo file | cut -f1
file

If you are looking to get at the first column, you will have to process that file.

Code:

$ seq -s'      ' 0 1 10 > file
$ seq -s'      ' 1 1 11 >> file
$ seq -s'      ' 2 1 12 >> file
$ cat file
0       1       2       3       4       5       6       7       8       9      10
1       2       3       4       5       6       7       8       9       10     11
2       3       4       5       6       7       8       9       10      11     12
$ cut -f1 file
0
1
2
$ cut -f1 file | head -n 1
0

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-- I'll provide you with reference points; if they dont work, refer to something else.

If you process text, this might make your life a little easier.

February 20th, 2008, 01:09 PM

corticus

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I think I got it,
it is returning the file name (it actually originally returned a set of characters from the name, then I started messing around with it), I see that was the original point of the shell

so I can use seq to grap the first line of the file
and then do cut on that

thanks, I'll go give it a try!

February 20th, 2008, 04:43 PM

L7Sqr

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Quote:

Originally Posted by corticus

so I can use seq to grap the first line of the file

No. the seq was only to fill the file with some tab separated data. (man seq for more details). It's what I did with the file afterwards that you should look at. Sorry for the misdirection there....
Here are the relevant sections:

Code:

$ cut -f1 file
0
1
2
$ cut -f1 file | head -n 1
0

February 21st, 2008, 02:06 AM

SimonJM

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Just as a passing point, if you just want the first field of first line from file, it is better (more efficient) to do the head first, then the cut.

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February 25th, 2008, 12:58 AM

ghostdog74

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just use awk, no need for cut or head

Code:

LSID=`awk 'NR==1{print $1;exit}' file`

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