Mastodawn

Woozle Hypertwin Feb 5, 2020

The convention of having the command shell replace "*" with a list of all matching files in the current folder[1] only in is... well.

I understand how it's useful for really basic core file utilities.

For anything that needs to do recursive directory-searches, though, it really gets in the way and raises the bar for what the user has to know in order to make use of CLI in Linux.

I just now had a long conversation with an advanced bash user[2], and apparently there really is no way to get this information without setting an option in bash before running a command (and then presumably unsetting it afterwards, so as not to break other programs).

Just... why.

#softwareGripe

[1] ...and *only* the current folder... and only including folders that match the same pattern -- like "*.rb" would include a folder named "foldername.rb", which pretty much never happens

[2] Much thanks to sophia kara for hashing through this with me. I was very grumpy about it.

Show thread

Doc Edward Morbius ❌Feb 5, 2020

@woozle 1. What option is this?

2. Globbing is a convenience, but generally *Not Good Programming Practice*.

3. find | read or find | xargs is probably what you want. More specifically:

while find . <args> | read file do; echo ">>> $file <<<"; <processing on file>; done

I like to echo the name of the file(s) found, first, both as a verification of the find command/results, and as a progress indicator.

Show thread

Woozle Hypertwin Feb 5, 2020

@dredmorbius

#1: I've documented my findings -- https://htyp.org/bash/globbing

#2: Hard agree -- especially when there's no way to access the raw information (without making the user jump through extra hoops to provide it).

#3: I'd consider this an "extra hoop".

It seems to me that bash needs to be patched to provide the information in the execution environment. It already provides all kinds of other information of more dubious value, e.g. the format of the command-prompt, so why not this?

Show thread

Doc Edward Morbius ❌Feb 6, 2020

@woozle Bash is (at least) two things:

1. An interactive command environment.

2. A scripting tool.

The *benefit* of combining these features is that _what you use daily to interact with the system_ is *also* what you can use _for basic system automation tasks_.

In fact you can segue from one to the other through "shell one-liners" and the like. As a consequence, bash is the one programming tool I know best, _simply from daily familiarity_.

The combination also forces compromises.

Show thread

Doc Edward Morbius ❌

@woozle You might arguably have globs match regex patterns. There are ways to achieve this, but the shell itself doesn't.

(There *are* advanced glob patterns, though, should you care to use them. That's an area of bash I'm still not very familiar with.)

Historically, globbing predates regexes, though.

And you could have globs span directory path boundaries. For various reasons, that isn't done. It strikes me as dangerous, especially if you end up with a */../* type pattern.