Append line to many files

Question

I want to add some text to over 200,000 files I am trying this

find . -name *.txt -print | xargs -I % echo "hello world" >> %

But nothing is happening. When i run find . -name *.txt it work by itself as does echo "hello world" >> myfile.txt

Mikel · Accepted Answer · 2012-05-03 03:58:34Z

The shell is expanding the >> % part before xargs sees it.

If you need to do shell redirections, you'll have to try something like this:

find . -name "*.txt" -exec sh -c '
    echo "hello world" >> "$0"
    ' {} \;

How it works:

find replaces {} with each file that it matches
bash -c "some command" arg0... sets $0... inside the "some command" script

Alternatively, you could use a command such as sed that doesn't rely on >> e.g.

find . -name "*.txt" -exec sed -i -e '$a\
hello world' {} \;

References:

That sed command will append 'hello world' after each line. You need sed -i '$ahello world' to put it only at the end of the file (my testing with GNU sed did not need the backslash-newline)

Ole Tange · Answer 2 · 2012-05-09 18:33:22Z

With GNU Parallel you can do:

find . -name *.txt -print | parallel 'echo "hello world" >> {}'

You can install GNU Parallel simply by:

wget http://git.savannah.gnu.org/cgit/parallel.git/plain/src/parallel
chmod 755 parallel
cp parallel sem

2 Answers