Bash String Remove Specific Characters

I'm almost done开发者_高级运维 with using bash, but the last thing I need to do is to do a regex replace on a string in bash. I have the PHP equivalent here

preg_replace("/[^a-z0-9\.]/", '',$theme_name);

I need to do this exact same thing in bash, which is replacing every non alphanumeric character or dots (.) with nothing. Thanks in advance!

Try the following:

echo "some string" | tr -d -c ".[:alnum:]"

• tr "translates" characters in the string
• -d deletes instead of translates
• -c means complement
• [:alnum:] means "alpha numerics".

Try this

echo "hello world" | sed  -e 's/[reg_ex]//g'