How to use sed to change file extensions?

Question

I have to do a sed line (also using pipes in Linux) to change a file extension, so I can do some kind of mv *.1stextension *.2ndextension like mv *.txt *.

Answer 1

This may work:

find . -name "*.txt" | 
sed -e 's|./||g' | 
awk '{print "mv",$1, $1"c"}' | 
sed -e "s|\.txtc|\.c|g" > table;
chmod u+x table;
./table

I don't know why you can't use a loop. It makes life much easier :

newex="c";  # Give your new extension
for file in *.*;  # You can replace with *.txt instead of *.*
do 
 ex="${file##*.}";    # This retrieves the file extension
 ne=$(echo "$file" | sed -e "s|$ex|$newex|g"); # Replaces current with the new one
 echo "$ex";echo "$ne";
 mv "$file" "$ne";
done

Answer 2

You may try following options

Option 1 find along with rename

find . -type f -name "*.ext1" -exec rename -f 's/\.ext1$/ext2/' {} \;

Option 2 find along with mv

find . -type f -name "*.ext1" -exec sh -c 'mv -f $0 ${0%.ext1}.ext2' {} \;

Note: It is observed that rename doesn't work for many terminals

Answer 3

You can use find to find all of the files and then pipe that into a while read loop:

$ find . -name "*.ext1" -print0 | while read -d $'\0' file
do
   mv $file "${file%.*}.ext2"
done

The ${file%.*} is the small right pattern filter. The % marks the pattern to remove from the right side (matching the smallest glob pattern possible), The .* is the pattern (the last . followed by the characters after the .).

The -print0 will separate file names with the NUL character instead of \n. The -d $'\0' will read in file names separated by the NUL character. This way, file names with spaces, tabs, \n, or other wacky characters will be processed correctly.

Answer 4

you can use string manipulation

filename="file.ext1"
mv "${filename}" "${filename/%ext1/ext2}"

Or if your system support, you can use rename.

Update

you can also do something like this

mv ${filename}{ext1,ext2}

which is called brace expansion

Answer 5

sed is for manipulating the contents of files, not the filename itself. My suggestion:

rename 's/\.ext/\.newext/' ./*.ext

Or, there's this existing question which should help.

Answer 6

Another solution only with sed and sh

printf "%s\n" *.ext1 | 
sed "s/'/'\\\\''/g"';s/\(.*\)'ext1'/mv '\''\1'ext1\'' '\''\1'ext2\''/g' | 
sh

for better performance: only one process created

perl -le '($e,$f)=@ARGV;map{$o=$_;s/$e$/$f/;rename$o,$_}<*.$e>' ext2 ext3