Replacing one char with many chars with using tr

Question

  `echo "a~b" | tr '~' "=="`

This outputs a=b. But i wanted a==b. How can i do this with using tr?

Answer 1

tr just can translate/delete characters.

Try something like this:

 echo "a~b" | sed 's/~/==/g'

Answer 2

You can't with tr.

Instead, use bash string manipulation ${string/substring/replacement}. Example:

str="a~b"
echo ${str/"~"/"=="}

Or use sed:

echo "a~b" | sed 's/~/==/'

Answer 3

You can't; tr can only map single characters. Use sed.