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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
 

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LEARN ABOUT DEBIAN

calife.auth

CALIFE.AUTH(5)						      BSD File Formats Manual						    CALIFE.AUTH(5)

NAME

     calife.auth -- format of the calife authorization file

DESCRIPTION

     The calife.auth files are files consisting of newline separated records, one per user, containing three colon (``:'') separated fields.
     These fields are as follows:

	   name   User's login name / @group.

	   shell  User's shell

	   user1,user2,...,usern
		  List of logins allowed for the user name

     The name field is the login used to access the computer account.

     The login name must never begin with a hyphen (``-''); also, it is strongly suggested that neither upper-case characters or dots (``.'') be
     part of the name, as this tends to confuse mailers.  No field may contain a colon (``:'') as this has been used historically to separate the
     fields in the user database.

     One alternative syntax is to use @group to specify that any user in the given group is allowed to use calife to become root.

     The shell field is the command interpreter the user prefers.  If there is nothing in the shell field, the user's current shell as found in
     the (/etc/passwd) file is assumed.

     If the shell field is '*', then the account is considered as locked and access is denied.

     If the third parameter is specified, it is assumed to be the list of login the current user has the right to become. It enables use of calife
     for non-root only accounts.

     calife.auth is placed in /etc.

EXAMPLE

     # calife.auth-dist
     #
     # Format
     #
     # name[:shell_to_be_run][:user1,user2,usern]
     #
     fcb
     roberto:/bin/tcsh
     pb::guest,blaireau

SEE ALSO

     calife(1), su(1)

HISTORY

     A calife.auth file format appeared in DG/UX and SunOS, written for Antenne 2 in 1991. It has evolved with the extra shell specification. The
     login list was reintroduced in 2.7.

AUTHOR

     Ollivier Robert <roberto@keltia.frmug.fr.net>

BSD
								September 25, 1994							       BSD
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