Login or Register to Ask a Question and Join Our Community

Sponsored Content
Full Discussion: Update file record inside read loop
Top Forums Shell Programming and Scripting Update file record inside read loop Post 302742631 by Corona688 on Tuesday 11th of December 2012 11:03:09 AM
Old 12-11-2012
Not really, no. There is no seamless 'insert' operation for a file. To add extra data to the middle of a file, you must rewrite all the data that comes after it. That is why inserting data is so complicated, you never really do so.

The usual solutions for doing it all in one step, ed or sed -i, still use a temp file in many implementations.

So, since your records aren't fixed-width, the answer is no. If they were fixed-width, you could change any record without changing the length of the line, making it more possible, but fixed-width records are a difficult thing to handle in shell!
Last edited by Corona688; 12-11-2012 at 12:09 PM..
 

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

read inside a while loop

Hi all, In a while loop, like below... while read line do read choice case $choice in 1) echo "xxx" esac done < file why I can't run the read choice???? (3 Replies)
Discussion started by: dta4316
3 Replies

2. Shell Programming and Scripting

input inside while read loop

Hi all Does anyone have a script that will allow me to stop inside a while read loop. I want to pause the loop until a enter is pressed. e.g. While read line do echo something if LINECOUNT > 40 then read ENTER?"PRESS ENTER TO CONT..." ... (3 Replies)
Discussion started by: jhansrod
3 Replies

3. UNIX for Dummies Questions & Answers

how to read record by record from a file in unix

Hi guys, i have a big file with the following format.This includes header(H),detail(D) and trailer(T) information in the file.My problem is i have to search for the character "6h" at 14 th and 15 th position in all the records .if it is there i have to write all those records into a... (1 Reply)
Discussion started by: raoscb
1 Replies

4. Shell Programming and Scripting

read command (input) inside the while loop

Hi, 'read' command is not working inside the while loop, How can I solve this? Rgds, Sharif. (2 Replies)
Discussion started by: sharif
2 Replies

5. UNIX for Advanced & Expert Users

"while read ..." loop exiting after reading only one record

Greeting, The following script completes after reading only one record from the input file that contains many records. I commented out the "ssh" and get what I expect, an echo of all the records in the input.txt file. Is ssh killing the file handle? On the box "uname -a" gives "SunOS... (2 Replies)
Discussion started by: twk
2 Replies

6. Shell Programming and Scripting

how to pass a variable to an update sql statement inside a loop

hi all, i am experiencing an error which i think an incorrect syntax for the where clause passing a variable was given. under is my code. sqlplus -s ${USERNAME}/${PASSWORD}@${SID} << END1 >> $LOGFILE whenever sqlerror exit set serveroutput on size 1000000 declare l_rc ... (0 Replies)
Discussion started by: ryukishin_17
0 Replies

7. Shell Programming and Scripting

Unable to read the first space of a record in while loop

I have a loop like while read i do echo "$i" . . . done < tms.txt The tms.txt contians data like 2008-02-03 00:00:00 <space>00:00:00 . . . 2010-02-03 10:54:32 (2 Replies)
Discussion started by: machomaddy
2 Replies

8. Shell Programming and Scripting

For loop inside awk to read and print contents of files

Hello, I have a set of files Xfile0001 - Xfile0021, and the content of this files (one at a time) needs to be printed between some line (lines start with word "Generated") that I am extracting from another file called file7.txt and all the output goes into output.txt. First I tried creating a for... (5 Replies)
Discussion started by: jaldo0805
5 Replies

9. Shell Programming and Scripting

ksh while read loop breaks after one record - AIX

#!/bin/ksh for SRV in imawasp01 \ imawasp02 \ imawasp03 \ imawasp04 \ imawasp05 \ imawasp06 \ imawasp07 \ imawasp08 \ imawasp09 do print "${SRV}" while read PASSLINE do SRVNAME=`echo ${PASSLINE} | awk -F\: '{print $1}'` LASTLOGIN=`ssh ${SRV} lsuser ${SRVNAME} | tr '... (2 Replies)
Discussion started by: port43
2 Replies

10. Shell Programming and Scripting

Unable to read user input inside a loop

Hi, This query is a part of a much more lengthy script. I wish to look for all the files in a folder named "data" which in this case has two files i.e. plan.war and agent.properties. For all the files found under data I wish to ask the user as to where they wish copy the files to. Below,... (14 Replies)
Discussion started by: mohtashims
14 Replies

LEARN ABOUT DEBIAN

tinydyndns-update

tinydyndns-update(8)					      System Manager's Manual					      tinydyndns-update(8)

NAME

       tinydyndns-update - update TYPE A record in data.cdb

SYNOPSIS

       tinydyndns-update fqdn dynip

DESCRIPTION

       tinydyndns-update  changes  the data of a TYPE A record in data.cdb in the current directory.  Other than tinydns-data(8), tinydndns-update
       does not know about the source file data but changes the binary database data.cdb directly.

       First tinydyndns-update checks if the given fqdn has a TYPE A record in data.cdb.  Then it checks if the given IP address differs from  the
       one  in	the  TYPE  A record in data.cdb, or if the record's timestamp should be updated.  Finally if data.cdb needs to change, tinydyndns-
       update copies data.cdb to data.tmp, changes the IP address of the TYPE A record of fqdn to dynip in data.tmp, optionally  adjusts  time-to-
       live or time-to-die, and renames data.tmp to data.cdb.

ENVIRONMENT

       TTL    time-to-live.  The environment variable TTL overrides the default time-to-live in seconds (0 if TTD is set, otherwise 5).  If TTL is
	      not set or zero, the time-to-live of the record will not change.	$TTL must be an integer.

       TTD    time-to-die.  $TTD must be an integer, specifying a number of seconds.  If TTD is set, the timestamp of the record  is  set  to  the
	      current  time  plus  $TTD  seconds,  and TTL is set to zero by default, so that tinydns(8) interpretes the timestamp as time-to-die.
	      Note: you probably want to adjust SOA ttl, or create a wildcard record, to prevent DNS caches from caching nxdomain, when using this
	      feature.

       LOC    location.  $LOC must be two characters long.  If LOC is set, it specifies the client location for records to be updated.

EXIT CODES

       If tinydyndns-update cannot find a TYPE A record for fqdn in data.cdb, it prints a warning and exits 114.

       If  dynip  does not differ from the IP address of the TYPE A record of fqdn in data.cdb, and the environment variable TTD is not set, tiny-
       dyndns-update prints a note and exits 0.

       tinydyndns-update exits 100 if it has trouble opening data.cdb, and leaves data.cdb unchanged.

       tinydyndns-update exits 111 on temporary error, and leaves data.cdb unchanged.

       If data.cdb was changed successfully, tinydyndns-update exits 0.

FILES

	./data.cdb
	./data.tmp

SEE ALSO

       tinydyndns-data(8), tinydyndns-conf(8)

       http://smarden.org/tinydyndns/

AUTHOR

       Gerrit Pape <pape@smarden.org>

															      tinydyndns-update(8)
All times are GMT -4. The time now is 03:45 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy