Compare 2 directories and copy differences to directory 3 - linux

Question

I have three directories. I would like to compare directory1 with directory2, then take those changes/new files and copy them over to directory3. Is there an easy way to do this, maybe by using linux diff and cp commands? I'm open to ideas.
Thanks!
Andrew

Answer 1

I believe this is what you want from your description.
for file in dir2/*; do
file_in_dir1=dir1/$(basename ${file})
if [ ! -e ${file_in_dir1} ]; then
# If the file in dir2 does not exist in dir1, copy
cp ${file} dir3
elif ! diff ${file} ${file_in_dir1}; then
# if the file in dir2 is different then the one in dir1, copy
cp ${file} dir3
fi
done
One thing I wasn't sure about is what you wanted if a file exists in dir1 but not dir2.

Answer 2

The thread yonder solves your problem quite nicely, I should think!
Copied from there:
#!/bin/bash
# setup folders for our different stages
DIST=/var/www/localhost/htdocs/dist/
DIST_OLD=/var/www/localhost/htdocs/dist_old/
DIST_UPGRADE=/var/www/localhost/htdocs/dist_upgrade/
cd $DIST
list=`find . -type f`
for a in $list; do
if [ ! -f "$DIST_OLD$a" ]; then
cp --parents $a $DIST_UPGRADE
continue
fi
diff $a $DIST_OLD$a > /dev/null
if [[ "$?" == "1" ]]; then
# File exists but is different so copy changed file
cp --parents $a $DIST_UPGRADE
fi
done

Answer 3

You can also do it without a bash script:
diff -qr ./dir1 ./dir2 | sed -e 's/^Only in\(.*\): \(.*\)/\1\/\2/g' -e 's/ and \..*differ$//g' -e 's/^Files //g' | xargs -I '{}' cp -Rf --parents '{}' ./dir3/
This solution removes all additional text from the diff command using sed, and then copies the files preserving the directory structure.

Answer 4

The two previously posted answers helped me get started but didn't get me all the way there. The solution posted by thomax was really close but I ran into an issue where the cp command on osx doesn't support the --parents parameter so I had to add some logic around the creation of subfolders which made things a bit messy and I had to restructure a bit. Here's what I wound up with:
#!/bin/bash
# setup folders for our different stages
DIST=/var/www/localhost/htdocs/dist/
DIST_OLD=/var/www/localhost/htdocs/dist_old/
DIST_UPGRADE=/var/www/localhost/htdocs/dist_upgrade/
cd $DIST
find . -type f | while read filename
do
newfile=false
modified=false
if [ ! -e "$DIST_OLD$filename" ]; then
newfile=true
echo "ADD $filename"
elif ! cmp $filename $DIST_OLD$filename &>/dev/null; then
modified=true
echo "MOD $filename"
fi
if $newfile || $modified; then
#massage the filepath to not include leading ./
filepath=$DIST_UPGRADE$(echo $filename | cut -c3-)
#create folder for it if it doesnt exist
destfolder=$(echo $filepath | sed -e 's/\/[^\/]*$/\//')
mkdir -p $destfolder
#copy new/modified file to the upgrade folder
cp $filename $filepath
fi
done

Answer 5

Consider you have dir1, dir2 and dir3 on the same level
with the content setup as below:
mkdir dir1
mkdir dir2
echo 1 > dir1/a
echo 1 > dir2/a
echo 2 > dir1/b
echo 3 > dir2/b
echo 4 > dir2/c
cp -r dir1 dir3
When you create and apply patch like this:
diff -ruN dir1 dir2 | patch -p1 -d dir3
Then you have content of dir2 and dir3 equivalent.
If your dir2 is not at the same level as dir1
then you have to edit filenames in the patch
so that you have equal amount of path components
in both dir1 and dir2 filenames.
You should better put your dir2 to the same level as dir1,
because there is no elegant way to do this (at least known to me).
Here follow an "ugly" way.
Consider your dir2 is located in some $BASEDIR
then you should update your diff to trim of the $BASEDIR from dir2's path
like this
diff -ruN dir1 $BASEDIR/dir2 | \
perl -slne 'BEGIN {$base =~ s/\//\\\//g; print $base}
s/\+\+\+ $base\//\+\+\+ /g; print' \
-- -base=$BASEDIR
And then you could apply the resulting path as above.