3 ms·

> Quoting is building execve's argv parameter. can you expand on this? does this elucidate, e.g., variable substitution and the difference between single- and

• koala_man 9y ago
  The behavior of quotes can and should be described in terms of how they affect the words they expand to (i.e. the argv you build), so yes, it clarifies all this. For example, all the various wrong ways of quoting var="My File.txt" or otherwise incorrectly using such a name will result in variations on a wrong argument list: execlp("cat", "$var", NULL); // cat '$var' execlp("cat", "My", "File.txt", NULL); // cat $var execlp("cat My File.txt", NULL); // cmd="cat $var"; "$cmd" execlp("cat", "'My", "File.txt'", NULL);// cmd="cat '$var'"; $cmd execlp("cat", "My\\", "File.txt", NULL);// cmd="cat My\ File.txt"; $cmd execlp("cat", "'My File.txt'", NULL); // var="'$var'"; cat "$var" execlp("cat", "\"$var\"", NULL); // arg='"$var"'; cat $arg Meanwhile, all the correct ones result in the same, correct argv: execlp("cat", "My File.txt", NULL); // cat "$var" execlp("cat", "My File.txt", NULL); // cat 'My File.txt' execlp("cat", "My File.txt", NULL); // cat "My File.txt" execlp("cat", "My File.txt", NULL); // cat My\ File.txt execlp("cat", "My File.txt", NULL); // cmd=("cat" "$var"); "${cmd[@]}" execlp("cat", "My File.txt", NULL); // arg="'My File.txt'"; eval "cat $arg" If you don't know which argument list you're aiming for, you basically have to go by guesswork and superstitions.