Shell Programming and Scripting

hi guys,

Suppose you have 100 files in a folder and you want to replace all occurances of a word say "ABCD" in those files with "DCBA", how would you do
it ???

jatin

hi,

try this,

cd <your_folder>
ls > out.sh

vi out.sh

:%s/^/perl -pi -e 's\/ABCD\/DCBA\/' /

save and exit

sh out.sh

and bingo....

"perl -pi -e 's/abcd/dcba/' filename" will basically do the substitution and listing all the files in a file then prepending this string in front of each filename, will produce a shell script out.sh which would run this perl command on each of the files.

hope it helps
asif

If I understand what you're asking, this code should do what you want (ksh):

cd your_pathname
for i in `lx`; do
FOUND=`grep ABCD $i`
if [ "$FOUND" ]
then
TMP=./tmpfile_$$
sed -e 's/ABCD/DCBA/g' < $i > $TMP
mv $TMP $i
else
echo "The file $i does not include the word ABCD"
fi
done

This script reads each file in your_pathname, searches for the string ABCD, and either replaces it with DCBA or alerts you that the string ABCD was not found.

This is a bit simplier.

for y in `ls *`;
do sed "s/ABCD/DCBA/g" $y > temp; mv temp $y;
done

well there are so many different ways of doing it.

but what i am suggesting is why unnecessary create a temporary file when you can do without.

also, any suggestions from anyone, which of the above mentioned methods would be fastest.

I would bet that peter's is faster...

You could make it a split second faster by getting rid of the `ls *` though...

If could just be:
for y in *
since the shell will expand the * into all of the file names...
If you had directories in there, you'd want to use "find" to get only the files...

remember you are redirecting output to a file and then moving the file back to the original
what if the file sizes are of the order of tens of MBs.
secondly, the shell script would compulsorily do it for all the files in the directory.
but while using a file, you can customize your renaming process.