Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Using AWK in a for loop
Top Forums Shell Programming and Scripting Using AWK in a for loop Post 302347292 by Jahn on Tuesday 25th of August 2009 10:32:25 AM
Old 08-25-2009
Using AWK in a for loop
Hello,

I am trying to use AWK to print only the first field of numerous text files, and then overwrite these files. They are of the format 1*2,3,4,5. I have tried the following code (using tcsh):

Code:
 foreach f (file1 file2 file3)
cat $f | awk -F'*' '{print $1}' > $f
end

However, I get very inconsistent results each time I run this script. I have tried creating a tmp directory where I run the above command on a clean set of the files. But, sometimes it returns empty files, whereas other times it runs fine for all the files. Any ideas on what is going on here, or if there is a better way to get awk to do what I want?

On a side note, I have tried a similar method using cut:

Code:
 foreach f (file1 file2 file3)
cat $f | cut -d'*' -f1 > $f
end

but I get the same inconsistencies.


Thank you for your help,

-Jahn
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

for loop in awk?

I am new to unix and have pieced together two scripts that work independently. The first checks all the filesystems and reports which are running low on space. df -m | awk 'int($4) > 75 { print $1 " has only " $3 "mb free from a total of " $2 ", this filesystem is " $4 " full! \n" }... (1 Reply)
Discussion started by: Bdawk
1 Replies

2. Shell Programming and Scripting

awk for-loop and NR

Hey, I know this is a stupid question, but it doesn't work. I have a file with 10 lines and I want to pipe the content to awk and then print line 1 til 2 into another file and then line 3-4 ... So my script looks like that, but doesn't work: cat grid_ill.pts | awk '{ for (NR=1;NR<3;NR++)... (8 Replies)
Discussion started by: ergy1983
8 Replies

3. Shell Programming and Scripting

Comparison and editing of files using awk.(And also a possible bug in awk for loop?)

I have two files which I would like to compare and then manipulate in a way. File1: pictures.txt 1.1 1.3 dance.txt 1.2 1.4 treehouse.txt 1.3 1.5 File2: pictures.txt 1.5 ref2313 1.4 ref2345 1.3 ref5432 1.2 ref4244 dance.txt 1.6 ref2342 1.5 ref2352 1.4 ref0695 1.3 ref5738 1.2... (1 Reply)
Discussion started by: linuxkid
1 Replies

4. Shell Programming and Scripting

awk - loop from a to z

Hello, I was wondering if it is possible to do a loop on letters rather than numbers with awk (gawk). Basically I used to do: echo "nothing" | gawk '{for(i=1;i<11;i++)print i}' But I would like to do something like that (which obviously does not work): echo "nothing" | gawk '{for(i in... (6 Replies)
Discussion started by: jolecanard
6 Replies

5. Shell Programming and Scripting

awk loop and using shell in awk

Hi, everyone! I have a file, when I print its $1 out it show several strings like this: AABBCC AEFJKLFG FALEF FAIWEHF What I want to do is that, after output of each record, search the string in all files in the same folder, print out the record and file name. This is what I want... (4 Replies)
Discussion started by: xshang
4 Replies

6. Shell Programming and Scripting

awk loop using array:wish to store array values from loop for use outside loop

Here's my code: awk -F '' 'NR==FNR { if (/time/ && $5>10) A=$2" "$3":"$4":"($5-01) else if (/time/ && $5<01) A=$2" "$3":"$4-01":"(59-$5) else if (/time/ && $5<=10) A=$2" "$3":"$4":0"($5-01) else if (/close/) { B=0 n1=n2; ... (2 Replies)
Discussion started by: klane
2 Replies

7. Shell Programming and Scripting

awk programming -Passing variable to awk for loop

Hi All, I am new to AWK programming. I have the following for loop in my awk program. cat printhtml.awk: BEGIN -------- <some code here> END{ ----------<some code here> for(N=0; N<H; N++) { for(M=5; M<D; M++) print "\t" D ""; } ----- } ... (2 Replies)
Discussion started by: ctrld
2 Replies

8. Shell Programming and Scripting

Using awk within a for loop

Hello, I currently have managed to get an awk function working inside a for loop that allows me to combine two files based on their headings but what I have not been able to do is print the output to files with variable names. awk ' NR==FNR {a=$0; next} /^>/ {$0 = $0" "a;} ... (2 Replies)
Discussion started by: Allie_gastrator
2 Replies

9. UNIX for Beginners Questions & Answers

awk with For loop

Hi My Requirement is to take the sum of each column below is the input file. 1 2 3 4 1 2 3 4 1 2 3 4 Initial i was using below command to achieve my desired result. however this was adding the row and not column. i am not able understand why this is happening awk... (1 Reply)
Discussion started by: scriptor
1 Replies

10. UNIX for Beginners Questions & Answers

awk !seen[$]++ in else loop

Hi all, I was searching the net for a solution for my problem... unfortunately nothing so far. I want to sort on more than on column tab delimited file and keep the line if in the column I sort there is no value, but for those who have a value I want them only unique. I have tried the... (5 Replies)
Discussion started by: ksenia
5 Replies

LEARN ABOUT HPUX

merge

merge(1)						      General Commands Manual							  merge(1)

NAME

       merge - three-way file merge

SYNOPSIS

       file1 file2 file3

DESCRIPTION

       combines  two  files  that are revisions of a single original file.  The original file is file2, and the revised files are file1 and file3.
       identifies all changes that lead from file2 to file3 and from file2 to file1, then deposits the merged text into file1.	If the	option	is
       used, the result goes to standard output instead of file1.

       An  overlap  occurs  if both file1 and file3 have changes in the same place.  prints how many overlaps occurred, and includes both alterna-
       tives in the result.  The alternatives are delimited as follows:

	      lines in file1
	      lines in file3

       If there are overlaps, edit the result in file1 and delete one of the alternatives.

       This command is particularly useful for revision control, especially if file1 and file3 are the ends of two branches that have file2  as  a
       common ancestor.

EXAMPLES

       A typical use for is as follows:

	      1.   To  merge  an  RCS branch into the trunk, first check out the three different versions from RCS (see co(1)) and rename them for
		   their revision numbers: 5.2, 5.11, and 5.2.3.3.  File 5.2.3.3 is the end of an RCS branch that split off the trunk at file 5.2.

	      2.   For this example, assume file 5.11 is the latest version on the trunk, and is also a revision  of  the  "original"  file,  5.2.
		   Merge the branch into the trunk with the command:

	      3.   File  5.11  now  contains  all  changes  made on the branch and the trunk, and has markings in the file to show all overlapping
		   changes.

	      4.   Edit file 5.11 to correct the overlaps, then use the command to check the file back in (see ci(1)).

WARNINGS

       uses the ed(1) system editor.  Therefore, the file size limits of ed(1) apply to

AUTHOR

       was developed by Walter F. Tichy.

SEE ALSO

       diff3(1), diff(1), rcsmerge(1), co(1).

																	  merge(1)
All times are GMT -4. The time now is 08:41 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy