Sed replacement not working when using variables [duplicate]

Question

something strange is happening when trying to replace string with sed. This works :

find /home/loni/config -type f -exec sed -i 's/some_pattern/replacement/g' {} \;

So it works when I manually type the strings. But in the case below replacement doesn't occur :

find /home/loni/config -type f -exec sed -i 's/${PATTERN}/${REPLACEMENT}/g' {} \;

When I echo these two variables PATTERN and REPLACEMENT they have the correct values.

I'm trying to replace all occurences of pattern string with replacement string in all files in my config directory.

Answer 1

Try

find /home/loni/config -type f -exec sed -i "s/${PATTERN}/${REPLACEMENT}/g" {} \;

instead. The ' quotes don't expand variables.

Answer 2

Not sure if I got this right, but if you want to replace the ${PATTERN} with ${REPLACEMENT} literally you have to escape the dollar and maybe the braces, those are reserved characters in regular expressions:

find /home/loni/config -type f -exec sed -i -e 's/\$\{PATTERN\}/\$\{REPLACEMENT\}/g' {} \;