Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

A sed question

Posted on 2006-07-16
6
516 Views
Last Modified: 2010-04-21
Hello Experts,
I want to use sed to find the first occurence of a particular string, for example "foo.bar", in a file.
When the string is found, the entire line it is in is to be replaced by a constant text, for example "surprise".

Example:

chicago 999 123
denver 874 99676 X
chicago 654 foo.bar 9867
apache 8794 bar.bar 8994
jersey soprano foo.bar 19


foo.bar is on the 3rd and 5th lines. only the first occurence will be transformed to "surprise".

chicago 999 123
denver 874 99676 X
surprise
apache 8794 bar.bar 8994
jersey soprano foo.bar 19


ShalomC
0
Comment
Question by:shalomc
6 Comments
 
LVL 6

Expert Comment

by:bira
ID: 17119951
This script will do the work, altough not using sed.
create a file named "yourfile" with the lines

chicago 999 123
denver 874 99676 X
chicago 654 foo.bar 9867
apache 8794 bar.bar 8994
jersey soprano foo.bar 19

then run the script below

clear
flag=0
while read x
do
a=`echo $x |grep foo.bar`
  if [ $? = 0 -a $flag = 0 ] ; then
         echo surprise
         flag=1
         else echo $x
  fi
done < yourfile
0
 
LVL 40

Expert Comment

by:noci
ID: 17126648
Using the ed commands (like vi esc: commands)

---8<---
#!/bin/bash
ed -s yourfile <<EOX 2>/dev/null
/foo.bar/s/^.*$/surprise/
%p
Q
EOX
---8<---


0
 
LVL 51

Accepted Solution

by:
ahoffmann earned 500 total points
ID: 17131299
sed -e '/foo\.bar/s/^.*$/sunprise/' your-file
0
Free Tool: Postgres Monitoring System

A PHP and Perl based system to collect and display usage statistics from PostgreSQL databases.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

 
LVL 34

Expert Comment

by:James0628
ID: 17135713
ahoffmann,

 But that would change every line with foo.bar in it (Wouldn't it?) and they only wanted to change the first one.


 ShalomC,

 sed probably isn't the best tool for this.  It's just not designed to change a single occurrence of a target string like this.

 James
0
 
LVL 51

Expert Comment

by:ahoffmann
ID: 17136187
oops, missed the "first one"
this is a academic requirement for sed, you better use awk or perl for that
  awk '/foo\.bar/{if(f==0){print "sunprise";f++;next}}{print}' your-file
0
 
LVL 33

Author Comment

by:shalomc
ID: 17148151
thanks guys,
this was supposed to work on an AS400 server - IBM did not port awk nor perl.
eventually it turned out that there can be only one occurence of the string, so the points go to ahoffmann

ShalomC
0

Featured Post

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
CPU monthly average? 12 132
Java core in Solaris 10 1 296
OpenView NNM: Global Manager to Regional Manager connection fails 7 80
Field name with special character (Ñ) in Oracle 11 88
Installing FreeBSD… FreeBSD is a darling of an operating system. The stability and usability make it a clear choice for servers and desktops (for the cunning). Savvy?  The Ports collection makes available every popular FOSS application and packag…
Why Shell Scripting? Shell scripting is a powerful method of accessing UNIX systems and it is very flexible. Shell scripts are required when we want to execute a sequence of commands in Unix flavored operating systems. “Shell” is the command line i…
Learn how to get help with Linux/Unix bash shell commands. Use help to read help documents for built in bash shell commands.: Use man to interface with the online reference manuals for shell commands.: Use man to search man pages for unknown command…
This video shows how to set up a shell script to accept a positional parameter when called, pass that to a SQL script, accept the output from the statement back and then manipulate it in the Shell.

837 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question