Replace Characters...

UNIX for Beginners Q & A UNIX for Dummies Questions & Answers
1

In a file, How do I replace a set number of characters in each line?

For example.... substitute the first 54 characters of each line with mv?

Thanks!
Lisa

2

'sed' is your friend - sed1liners

sed 's/^.\{54\}/mv/' myFile.txt
3 
sed "s/^.\{54\}/mv/" x
4

Thank you so much.... it was exactly what I needed!!

Can I just ask.... is the "." considered a wildcard in this code?

5

Yes "." matches any character

6

vgersh99

I have a doubt in this. If i am inside the file that is
vi myFile.txt.
Then how can I use the command, should I use the sed word?

7

no, but use the same 'substitute' expression in the vi 'command' mode.

8

Thanks,

could you please explain me what does this command mean?

:%s/crmrl01/crmpl01/g

9 
:%s/crmrl01/crmpl01/g

: - vi command 'mode'
% - for ALL the lines in the files
s - substutute the following:
     string 'crmrl01' with string 'crmpl01'
g - Globally for each line [not just once (by default), byut for multiple occorences of
      string  'crmrl01'