Usage of tail command in .awk Post: 302901362

Sponsored Content

Contact Us Post Here to Contact Site Administrators and Moderators How to Post in the The UNIX and Linux Forums Usage of tail command in .awk Post 302901362 by Corona688 on Tuesday 13th of May 2014 01:46:03 PM

05-13-2014

Registered User

`` and $( ) are shell syntax, they do not work inside awk. If they are processed at all they will be processed once, before awk is run, by the shell.

It might be easier to use awk's built-in file processing loop than fighting it by cramming it all in BEGIN. Less duplicated logic.

How about this:

Code:

find path/to/folder -type f | xargs awk '
# Call this function whenever the filename changes
function flush(F) {
        if(L) {
                F=LF;
                sub(OLDNAME, NEWNAME, F);
                if(F == LF)
                        print "WARNING, outfile=infile" >"/dev/stderr";
                else
                {
                        print LINE[L] > LF; # Print last line first
                        for(N=1; N<L; N++) print LINE[N] > LF; # Print other lines in order
                        close(LF); # Close file to avoid too-many-files error
                }
                L=0; # Reset line number
        }

        LF=FILENAME; # Store filename
}

LF != FILENAME { flush(); }
# Store every line from current file
{ LINE[++L]=$0 }
# Have to flush the very last file too
END { flush(); }' OLDNAME="/abc" NEWNAME="/def"

Use nawk on Solaris.

Corona688

View Public Profile for Corona688

Visit Corona688's homepage!

Find all posts by Corona688

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

tail command

Hi , I have found a interesting thing about tail command: when I tried to use 'tail -1 *' to look at every file with the current derectory, I only got one line of result of one file. But if I use 'head -1 *', I would get multiple lines. Is there a way to do get multiple lines with 'tail -1 *'...

2. Shell Programming and Scripting

tail command..

I was wondering how can I do this I have file myfile.txt wc -l is: 5 000 000 I have to remove first 1 000 000 lines from header.. I tryed with tail -4000000 myfile.txt>newfile.txt but it does not work... any help??

3. Shell Programming and Scripting

awk and grep command usage

hi Can anyone explain me how these two commands awk and grep works in a ksh shell Thanks Babu

4. HP-UX

how can I find cpu usage memory usage swap usage and logical volume usage

how can I find cpu usage memory usage swap usage and I want to know CPU usage above X% and contiue Y times and memory usage above X % and contiue Y times my final destination is monitor process logical volume usage above X % and number of Logical voluage above can I not to...

5. Shell Programming and Scripting

Help with tail command

Hi All, My query seems to be silly but Iam unable to find where the exact problem lies. I have a script to unzip set of files here is the script #!/bin/ksh Count=`cat /home/gaddamja/Tempfile | wc -l` while do Filename=`cat /home/gaddamja/Tempfile |tail -$Count | head -1` cd...

6. UNIX for Dummies Questions & Answers

Command to display the space usage (memory usage) of a specific directory.

Hi all, Can you please tell me the command, with which one can know the amount of space a specific directory has used. df -k . ---> Displays, the amount of space allocated, and used for a directory. du -k <dir name> - gives me the memory used of all the files inside <dir> But i...

7. Shell Programming and Scripting

usage of AWK command under perl script

i have two files as shown below t1.txt: argument1 argu2 argu37 t2.txt: 22 33 44 i want o/p as argument1 22 argu2 33 argu37 44 i am trying to merge two file under perl script using following system("paste t1.txt t2.txt | awk...

8. Shell Programming and Scripting

tail command help

Hi does anyone know how to create a file using the tail command? My book has this file I need to create and it says to use the tail command and that it is possible but I have no idea. Thanks.

9. Shell Programming and Scripting

usage of Awk command for output

Hi Experts, I have a Text file generated as below; <NAME> NEW#<technicalName><TAB> <Version> OLD#<technicalName><TAB> <Version> e.g. CH_PPV_AUDIT_DISTRIBUTOR NEW#EL_CFG_FTP_DISTRIBUTOR 2.1.0.upc2 OLD#EL_CFG_FTP_DISTRIBUTOR 2.1.0.upc1...

10. UNIX for Beginners Questions & Answers

Tail -f Command help

Hi Team, Can anyone help me here: I have to access server logs via putty and these logs file is a trailing file (continously updating) with ERROR and WARNINGS... I need to know if I can pull this trailing file to a local drive so that I can do some higlighting on some keywords through Notepad...

LEARN ABOUT NETBSD

sleep

SLEEP(1)						    BSD General Commands Manual 						  SLEEP(1)

NAME

     sleep -- suspend execution for an interval of time

SYNOPSIS

     sleep seconds

DESCRIPTION

     The sleep utility suspends execution for a minimum of seconds.  It is usually used to schedule the execution of other commands (see EXAMPLES
     below).

     Note: The NetBSD sleep command will accept and honor a non-integer number of specified seconds.  This is a non-portable extension, and its
     use will nearly guarantee that a shell script will not execute properly on another system.

     When the SIGINFO signal is received, the estimate of the amount of seconds left to sleep is printed on the standard output.

EXIT STATUS

     The sleep utility exits with one of the following values:

     0	   On successful completion, or if the signal SIGALRM was received.

     >0    An error occurred.

EXAMPLES

     To schedule the execution of a command for 1800 seconds later:

	   (sleep 1800; sh command_file >& errors)&

     This incantation would wait half an hour before running the script command_file.  (See the at(1) utility.)

     To reiteratively run a command (with csh(1)):

	   while (1)
		   if (! -r zzz.rawdata) then
			   sleep 300
		   else
			   foreach i (*.rawdata)
				   sleep 70
				   awk -f collapse_data $i >> results
			   end
			   break
		   endif
	   end

     The scenario for a script such as this might be: a program currently running is taking longer than expected to process a series of files, and
     it would be nice to have another program start processing the files created by the first program as soon as it is finished (when zzz.rawdata
     is created).  The script checks every five minutes for the file zzz.rawdata, when the file is found, then another portion processing is done
     courteously by sleeping for 70 seconds in between each awk job.

SEE ALSO

     at(1), nanosleep(2), sleep(3)

STANDARDS

     The sleep command is expected to be IEEE Std 1003.2 (``POSIX.2'') compatible.

BSD
								  August 13, 2011							       BSD

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

tail command

Discussion started by: whatisthis

2. Shell Programming and Scripting

tail command..

Discussion started by: amon

3. Shell Programming and Scripting

awk and grep command usage

Discussion started by: ksmbabu

4. HP-UX

how can I find cpu usage memory usage swap usage and logical volume usage

Discussion started by: alert0919