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Replacing strings in various files

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# 1  
Old 02-26-2013
Replacing strings in various files
i'm trying to figure out the easiest way to replace a string:

Code:
pineapple  pineapple-reg
basketball basketball-reg
football foot-reg-ball

i'm storing the above in a file called wordstoreplace.txt

for each line above, the word in the first column is to be replaced by the word in the second column. is this possible?

i have 5 different files that have in them the words in the first column.

lets say the 5 files are called: file1, file2, file3, file4, file5


i want to replace the first column words in all 5 files.
Code:
while read line
do
firstcolword=$(echo $line | awk '{print $1}')
seccolword=$(echo $line | awk '{print $2}')
cat file1 | sed 's/$firstcolword/$seccolword/g' > file1-new
cat file2 | sed 's/$firstcolword/$seccolword/g' > file2-new
cat file3 | sed 's/$firstcolword/$seccolword/g' > file3-new
cat file4 | sed 's/$firstcolword/$seccolword/g' > file4-new
cat file5 | sed 's/$firstcolword/$seccolword/g' > file5-new
done < wordstoreplace.txt

i just know the above isn't efficient. any ideas?
# 2  
Old 02-26-2013
Code:
while read firstcolword seccolword
do
    sed -i.bak "s/$firstcolword/$seccolword/g" file1 file2 file3 file4 file5
done < wordstoreplace.txt

Last edited by balajesuri; 02-26-2013 at 11:28 AM..
This User Gave Thanks to balajesuri For This Post:
SkySmart
# 3  
Old 02-26-2013
This should be even more efficient:
Code:
cmd=
while read -r w1 w2
do      cmd="${cmd}s/$w1/$w2/g;"
done < wordstoreplace.txt
for i in file[1-5]
do      sed "$cmd" $i > $i.new
done

This User Gave Thanks to Don Cragun For This Post:
SkySmart
# 4  
Old 02-26-2013
Quote:
Originally Posted by balajesuri
Code:
while read firstcolword seccolword
do
    sed -i.bak "s/$firstcolword/$seccolword/g" file1 file2 file3 file4 file5
done < wordstoreplace.txt


what is the "-i.bak" doing?
# 5  
Old 02-26-2013
Quote:
Originally Posted by SkySmart
what is the "-i.bak" doing?
Some implementations of sed have a -i option that in this form creates a backup copy of the file (as file.bak in this case) and then edits the file in place. Some implementations do not have this option.

If your sed has this option and you don't mind creating a new file for the backup; instead of creating a new file for the update, you could combine my proposal with balajesuri's proposal and only need to run sed once:
Code:
cmd=
while read -r w1 w2
do      cmd="${cmd}s/$w1/$w2/g;"
done < wordstoreplace.txt
sed -i.old "$cmd" file[1-5]

This User Gave Thanks to Don Cragun For This Post:
SkySmart
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