Command to escape a string in bash

Question

I need a bash command that will convert a string to something that is escaped. Here\'s an example:

echo \"hello\\world\" | escape | someprog

Answer 1

In Bash:

printf "%q" "hello\world" | someprog

for example:

printf "%q" "hello\world"
hello\\world

This could be used through variables too:

printf -v var "%q\n" "hello\world"
echo "$var"
hello\\world

Answer 2

You can use perl to replace various characters, for example:

$ echo "Hello\ world" | perl -pe 's/\\/\\\\/g'
Hello\\ world

Depending on the nature of your escape, you can chain multiple calls to escape the proper characters.

Answer 3

Pure Bash, use parameter substitution:

string="Hello\ world"
echo ${string//\\/\\\\} | someprog