Re: Help with --regex in locate

[rhkramer@gmail.com]

Thanks -- I'll try that sometime tomorrow!

On Tuesday, December 03, 2019 07:24:49 PM David wrote:
> On Wed, 4 Dec 2019 at 01:36, <rhkramer@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.