On Wed, 4 Dec 2019 at 01:36, <rhkra...@gmail.com> wrote: > I always have trouble with all the rigamarole around quoting for the shell vs. > quoting for the regex (or quoting or not quoting for anything else). > > I don't know what it will take to get it to sink into my head. (Maybe in my > next life ;-)
Hi, yes, it's complicated and confusing. Here's a suggestion ... Apologies if some of the following is stating things that are obvious, I just try to give complete instructions. We can make a helper command that shows us exactly what the shell does to any arguments before it sends them to a command. First we need a name for this helper command. Let's use the name show_args.bash, but you can use whatever name you like. I suggest this name because it is unlikely to already be in use on your system. Let's check: $ type show_args.bash bash: type: show_args.bash: not found Ok, that name is not in use, so let's use it. We are not going to put this command into the PATH so name collision doesn't really matter, but I'm just giving ideas and trying to be thorough. Open your favourite editor and create a file that contains the next paragraph (use cut and paste if possible, it must be exactly as shown): #!/bin/bash printf '%s' "$# args:" printf ' [%s]' "$@" printf '\n' Save this file with the name: show_args.bash Now make that file executable: $ chmod -v u+x show_args.bash mode of 'show_args.bash' changed from 0640 (rw-r-----) to 0740 (rwxr-----) Now we have created a command that just displays the arguments that it receives from the shell. The command is in the current directory and not in the PATH, so we need to specify its location when invoking it: ./show_args.bash Here's what it shows for a couple of commands that you had trouble with. $ ./show_args.bash locate --regex \/\.gitignore 3 args: [locate] [--regex] [/.gitignore] The above shows that your attempt to put \. into the regex did not work because the shell removed that escape-quoting. $ ./show_args.bash locate --regex '/\.gitignore' 3 args: [locate] [--regex] [/\.gitignore] The above shows that adding single quotes prevented that quote removal and the \. remained in the regex argument that was seen by locate. A helper command like this is useful when trying to apply the explanations at: http://mywiki.wooledge.org/Quotes to your own requirements.
