Generating sh code from within sh: Escaping

Question

I have a shell variable (we shall call x) containing a string with shell meta characters. For example, I might have

abc  \"def\'s\"  ghi
         


        

Answer 1

sh has functions.

# quote() - Creates a shell literal
# Usage:  printf '%s\n' "...$( quote "..." )..."
quote() {
    printf \'
    printf %s "$1" | sed "s/'/'\\\\''/g"
    printf \'
}

Testing:

$ x='abc  "def'\''s"  ghi'

$ printf '%s\n' "$x"
abc  "def's"  ghi

$ printf '%s\n' "prog `quote "$x"`"
prog 'abc  "def'\''s"  ghi'

$ printf '%s\n' "prog $( quote "`pwd`" )"
prog '/home/ikegami/foo bar'

$ printf '%s\n' "$( quote "a'b" )"
'a'\''b'

$ printf '%s\n' "$( quote '-n' )"
'-n'

$ printf '%s\n' "$( quote '\\' )"
'\\'

$ printf '%s\n' "$( quote 'foo
bar' )"
'foo
bar'

---

A version that takes multiple arguments:

# quote() - Creates a shell literal
# Usage:  printf '%s\n' "$( quote "..." "..." "..." )"
quote() {
    local prefix=''
    local p
    for p in "$@" ; do
        printf "$prefix"\'
        printf %s "$p" | sed "s/'/'\\\\''/g"
        printf \'
        prefix=' '
    done
}