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Find and Replace based on values in an file

 
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# 1  
Old 12-14-2010
Question Find and Replace based on values in an file
I have a file in which I want to do multiple find and replace of strings. For a single replace I can implement:

sed -i 's/old/new/' <input_file>

I have a second file that contains the old and the new values like the arbitrary example below:

old new
xyz pqr
ab 756
rst pqr
... ...

The question is how can I take the second file as input and do the necessary replacements in my first file instead of running individual replace commands?

Thx,
Guss
# 2  
Old 12-14-2010
Code:
 
cat second_file | while read line
do
    old=${line%% *}
    new=${line##* }
    sed -i "s/$old/$new/g" first_file
done

# 3  
Old 12-14-2010
Thanks for your solution Anurag. A minor question though; what if I were to have tab de-limiters instead of space, how do I incorporate that?

-Guss
# 4  
Old 12-14-2010
Use TAB space instead of single space
Code:
old=${line%%<TAB>*}
new=${line##*<TAB>}

This User Gave Thanks to anurag.singh For This Post:
Gussifinknottle
 
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