There are a lot of ways to do this. The most portable two that I know of are `sed` and `od` - they're both POSIX.

    printf '\n\r\b\t\033[01;31m' | sed -n l

It does like... `read` style escapes - C-style.



`od` is a little more configurable...

    printf '\n\r\b\t\033[01;31m' |
    od -v -w12 -t c -t a -A n

     \n  \r  \b  \t 033   [   0   1   ;   3   1   m
     nl  cr  bs  ht esc   [   0   1   ;   3   1   m

If you wanna know what all of those options do you can look in `man od`, but I specify I want two types of escapes - the `-t c` backslash escapes and the `-t a` named characters.
The `-w` option used above is not POSIX-specified.

And here's a little shell function that will portably print out the octal values of each byte in its arguments - which, of course, `od` might handle as well with `-t o`:

<!-- language-all: lang-sh -->

    proctal() (LC_ALL=C
        for a do while [ -n "$a" ] 
        do printf %o\\n "'$a"
        a=${a#?}; done; done)  

That's a simple one. This is a little more complicated. It should be able to do what the shell-specific `printf -q` implementations can, though.

<!-- language: lang-sh -->

    bsq() (set -f; export LC_ALL=C IFS=\'
        for a do q=${a##*\'}; printf \'
        [ -n "${a#"$q"}" ] &&
            printf "%s'\''" ${a%\'*}
        printf "%s'\n'''''\n" "$q"; done |
        sed -n "/'''''"'/!H;1h;//!d;$!n;x;l' |
        sed -e :n -e '/\\$/N;s/.\n//;tn

Using out example string from earlier with a little additional:

    bsq "$(printf '\n\r\'\''b\t\033[01;31m')"



It's only slightly different. You might notice there's an extra `0` and an extra `\b`ackslash. This is to allow for easy translation to a `read` or a `%b` `printf` argument. For example:

    until [ $((i=$i+1)) -gt 5 ]
    do touch "\%$i$(printf 'hey\b \t;\n\033 ')"
    done   #just for ugly's sake

    bsq * | eval "
        printf '<%b>\n' $(tr \\n \ )
    " | tee /dev/fd/2 |
    sed -n l


    <\%1he  ;
    <\%2he  ;
    <\%3he  ;
    <\%4he  ;
    <\%5he  ;
    <\\%1hey\b \t;$
    \033 >$
    <\\%2hey\b \t;$
    \033 >$
    <\\%3hey\b \t;$
    \033 >$
    <\\%4hey\b \t;$
    \033 >$
    <\\%5hey\b \t;$
    \033 >$