What does the following commands do? 🤔

[limaceous-bushwhacker]

• set -f - I see this being used a lot. Google tells me it's to disable filename expansions; is it supposed to be always used when writing functions?
• set -- (cat ~/.local/share/lf/files) - I've no idea what this one does. It's included in some of the examples in Wiki/Tips e.g. https://github.com/gokcehan/lf/wiki/Tips#create-symlinks-soft--hard

Since we're at it I'd like to throw in a couple more queries I had -

1. Is $fx supposed to be quoted or not? I see sometimes it being quotes in the aforementioned Tips section but sometimes not?
2. Can we use \0 as as ifs?
3. How can I access the list of selected files outside lf? I'm aware of ~/.local/share/lf/files but it isn't always populated with the list? Am I missing something or this warrant creating an issue?

Thanks in advance for your time and thanks to the contributors for working on this great project :)

[michaelferon]

set is used to modify shell options and set positional parameters. set -f disables globbing. Run

echo *
set -f
echo *

to see the effect.

~/.local/share/lf/files contains a list of files which have been marked for copying (yanking) or moving (cutting). The first line of this file indicates the mode (copy or move). Using set in this way is entirely distinct from the way it is used just above. It is simply setting the positional parameters, so that $1 contains the mode of operation, and the remaining positional parameters contain the files marked for copying or moving.

1. bash splits parameters expansions on whitespace. It's considered good practice to quote parameter expansions to avoid unwanted field splitting.
2. Not sure about this as I haven't done this sorry :( but will look into it
3. You can access files which have been marked for copying or moving via ~/.local/share/lf/files. This doesn't include files which have been selected using the toggle command (mapped to <space> by default).

[michaelferon]

There is some discussion on using \0 as a file separator in #47, but I'm not sure what the status is.

[michaelferon]

To elaborate a bit, I think the benefit in some of these instances of using set -f is so that $fx can be left unquoted. This makes using $fx a bit easier because, assuming none of the files contain spaces, each line of $fx will be treated as single 'word' (and hence, in the case of set -- $(cat ~/.local/share/lf/files), each a single parameter). But if any of the files contain globbing characters, if left unquoted, they'll be interpreted as such. So disabling globbing in these instances is probably a smart thing to do.

[limaceous-bushwhacker]

Thank you so much for such an informative answer Michael. set -- (cat ~/.local/share/lf/files) appear to be a syntax to create arguments from within a function. I wasn't aware of this syntax before inspite of using *nix for years now.

From what I've seen looks like it's better to leave $f, $fs, $fx unquoted wherever possible. This throws me off since usually it's recommended to always quote the variables. I was curious why it's this way instead of just using NUL as a separator, that'd just remove all the confusion.

Now I'm curious about the difference between toggle and select 🤔

[michaelferon]

In general, parameters really should almost always be quoted, so your concern there is warranted. The examples in the wiki assume you have the following in your lfrc:

set ifs "\n"
set filesep "\n" # <- this is the default

As long as you have that set, you can safely leave $f $fs $fx unquoted. Without ifs set to \n, bash will split $fx on ANY whitespace it finds, and expansions of $fx, as well as set -- $(cat ~/.local/share/lf/files), could behave unexpectedly (you could, for example, end up deleting a file you did not intend to delete).

I don't ever use toggle or select directly as commands. I just use the spacebar to "toggle" files (as you probably do as well), and hjkl keys to move around. As far as I can tell, the select command just takes an argument and moves the cursor line to that argument in the current directory.

P.S. You can always switch to zsh, where all these quoting difficulties can be handled much more elegantly :)

[superiums]

set is used to modify shell options and set positional parameters. set -f disables globbing. Run

echo *
set -f
echo *

to see the effect.

~/.local/share/lf/files contains a list of files which have been marked for copying (yanking) or moving (cutting). The first line of this file indicates the mode (copy or move). Using set in this way is entirely distinct from the way it is used just above. It is simply setting the positional parameters, so that $1 contains the mode of operation, and the remaining positional parameters contain the files marked for copying or moving.

1. bash splits parameters expansions on whitespace. It's considered good practice to quote parameter expansions to avoid unwanted field splitting.
2. Not sure about this as I haven't done this sorry :( but will look into it
3. You can access files which have been marked for copying or moving via ~/.local/share/lf/files. This doesn't include files which have been selected using the toggle command (mapped to <space> by default).

i tried the cmds , but they have different actions:

in fish

% echo * : output is '*'
% set -f : nothing
% echo *: output files in current dir.

in bash

% echo * : output files in current dir.
% set -f : nothing
% echo *: output files in current dir.

are you sure set -f was used to disable glob ?