replacing specific lines in a file


 
Thread Tools Search this Thread
Top Forums Shell Programming and Scripting replacing specific lines in a file
# 1  
Old 09-29-2006
replacing specific lines in a file

Hi there
I have a file which has the lines


Code:
# Serial number for hostid
EXP_SERIAL_=""

These lines could be anywhere in the file as far as line numbers go, I would like replace these two lines with

Code:
# Serial number for hostid $var1
EXP_SERIAL_$var1="$var2"

Is there a quick and simple way for me to do this ?

cheers
# 2  
Old 09-29-2006
........................................

Last edited by gauravgoel; 09-29-2006 at 08:58 AM.. Reason: wrong solution
# 3  
Old 09-29-2006
use this
Quote:
sed "s/old text/new text/g" input.txt
though not clean, should work

Last edited by gauravgoel; 09-29-2006 at 09:10 AM..
# 4  
Old 09-29-2006
thats great but if i run that command from the command line it outputs the correct result to the screen but doesnt actually edit the file


How do i get it to make a permanent change to the file ??
# 5  
Old 09-29-2006
Code:
sed "s/old text/new text/g" input.txt > temp
mv temp input.txt

or

Code:
perl -pi -e "s/old text/new text/g" input.txt

# 6  
Old 09-29-2006
that works great thankyou ....I wanted to avoid creating a new file and mv'ing it back over again....but if i have to do that then so be it

thanks for your help
# 7  
Old 09-30-2006
You might try something like this if you don't want to create a file:
Code:
echo '%s/oldtext/newtext/g\nwq' | ex file

This will edit the text within the file. Non interactive style vi. The exact syntax for ex is a bit murky I can't find a lot of docs on it, but in a few occasions it's well worth figuring out and using.
Login or Register to Ask a Question

Previous Thread | Next Thread

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Matching and Replacing file lines starting with $

Here is the task that I was presented with: I am dealing with about a 10,000 line input deck file for an analysis. About 10 separate blocks of around 25 lines of code each need to be updated in the input deck. The input deck (deckToChange in the code below) comes with 2 separate files. File 1... (5 Replies)
Discussion started by: tiktak292
5 Replies

2. UNIX for Dummies Questions & Answers

Quick UNIX command to display specific lines in the middle of a file from/to specific word

This could be a really dummy question. I have a log text file. What unix command to extract line from specific string to another specific string. Is it something similar to?: more +/"string" file_name Thanks (4 Replies)
Discussion started by: aku
4 Replies

3. Shell Programming and Scripting

Summing over specific lines and replacing the lines with the sum

Hi friends, This is sed & awk type question. It is slightly different from my previous question. I have a text file which has numbers spread all over the file. I want to sum the series of numbers (but no more than 10 numbers in series) whenever i find it and produce an output file with the... (4 Replies)
Discussion started by: kaaliakahn
4 Replies

4. Shell Programming and Scripting

Summing over specific lines and replacing the lines with the sum using sed, awk

Hi friends, This is sed & awk type question. I have a text file which has numbers spread all over the file. I want to sum the series of numbers whenever i find it and produce an output file with the sum. For example ###start of input text file #### abc def ghi 1 2 3 4 kjld random... (3 Replies)
Discussion started by: kaaliakahn
3 Replies

5. Shell Programming and Scripting

Replacing specific lines with another lines

Hi, I have a file with many lines, then i have following list of lines(line number 5,12,19,5,and 28) i need to replace these lines of a file with another lines as shown below these text contains special charecter like= (/:;){} Line_number Text to replace with 5 abc... (1 Reply)
Discussion started by: MILAN KUMAR
1 Replies

6. UNIX for Dummies Questions & Answers

Replacing all cells that have a specific value in a text file

I have a space delimited text file where I want to replace all cells that are 0 with NA. However I cannot simply use 'sed/0/NA/g' because there are other 0's in the text file that are part of numbers. Example input: 896.933464285715 0 874.691732142857 866.404660714286 Output:... (1 Reply)
Discussion started by: evelibertine
1 Replies

7. Shell Programming and Scripting

replacing field in specific line in a file

Hi, I know there are lots of threads on replacing text within files, usually using sed or awk. However, I find it hard to adapt examples that I found to my specific case. I am kind of new to UNIX and have hard times learning the syntax either for sed or awk so I would appreciate any help. Here's... (5 Replies)
Discussion started by: vytenis
5 Replies

8. Shell Programming and Scripting

Replacing Block of lines in a text file

Dear All, Regards of the Day. I have a text file with some functions: Function1 { parameter 1 parameter 2 parameter 3 } end Function2 { parameter 1 parameter 2 parameter 3 } (1 Reply)
Discussion started by: ashisharora
1 Replies

9. UNIX for Dummies Questions & Answers

how to display specific lines of a specific file

are there any basic commands that can display lines 99 - 101 of the /etc/passwd file? I'm thinking use of head and tail, but I forget what numbers to use and where to put /etc/passwd in the command. (2 Replies)
Discussion started by: raidkridley
2 Replies

10. UNIX for Advanced & Expert Users

replacing first line or lines in a file

hey guys, how do i replace only a line within a file without messing up the rest of the contents of the file? see, if possible can you guys give me a straight forward way to do this. i dont want a complex command. what i mean is i know i can accomplish this by using sed, well, i think i can,... (3 Replies)
Discussion started by: Terrible
3 Replies
Login or Register to Ask a Question