There I said it !
I think that providing an exit status that is not 0 when
zcatis used with an uncompressed file is useful. Though my opinion is less strong regarding whether it should write more text after an error occurred, it’s probably more useful for a process to terminate quickly when an error occurred rather than risk a second error occurring and making troubleshooting harder.I think that trying to change any existing documented features of widely used utilities will lead to us having less useful software in the future (our time is probably better spent making new programs and new documentation): https://www.jwz.org/doc/worse-is-better.html https://en.wikipedia.org/wiki/Worse_is_better
Not improving existing software leads to stagnation.
It’s certainly a good part of why so much of linux is an awkward kludgy idiosyncratic mess to use.
Whatever the first implementation does ends up being a suicide pact by default.
Another option is to change cat to auto decompress compressed files, instead of printing gibberish.
What operating system should I use with my laptop that isn’t an awkward kludgy idiosyncratic mess? I would say that Windows has plenty of kludges, like having problems with certain file names. Many versions of macOS are UNIX® Certified Products (for example, macOS version 15.0 Sequoia on Intel-based Mac computers and on Apple silicon-based Mac computers), so it’s surely not any less kludgy than Linux.
I suppose that it’s not bad to change documentation to be more specific, and change a program such that it matches the new documentation and wouldn’t cause any harm if it replaced all the existing versions of the program, but makes it possible to use the program to solve more problems. That would be to “add functionality in a backward compatible manner”.
You are also free to create new programs that are not an exact replacement for existing programs, but can enable some people to stop using one or more other programs. That would not be what I describe as stagnation.
“The cat utility shall read files in sequence and shall write their contents to the standard output in the same sequence.”, so I would be very annoyed if it did something different with a certain file but not others. I wouldn’t say that the contents of a file and the contents after the file is expanded are the same. In fact, I expect that some people use
catto process compressed files, and changing howcatacts with compressed files would probably cause them a large amount of annoyance, and would needlessly make a lot of existing documentation incorrect.
How do you propose zcat tell the difference between an uncompressed file and a corrupted compressed file? Or are you saying if it doesn’t recognize it as compressed, just dump the source file regardless? Because that could be annoying.
Even a corrupt compressed files has a very different structure relative to plain text. “file” already has the code to detect exactly which.
Still, failing on corrupted compression instead of failing on plaintext would be an improvement.
I agree. zgrep also works for uncompressed files, so we could use e.g.
zgrep ^instead of zcat.Thanks, didn’t know that existed
That’s basically everything I was looking for !
Yeah, it’s a pain. Leads to bad one liners:
for i in $(ls); do zcat $i || cat $i; doneBtw, don’t parse ls. Use
find |while read -rinstead.find -maxdepth 1 -name "term" -print |while read -r file do zcat "$file" 2>/dev/null || cat "$file" doneWon’t this cause cat to iterate through all files in the cwd once zcat encounters an issue, instead of just the specific file?
You are correct. This probably produces something more similar to what you’d want the original command to do, but with better safely:
find -- . -type f -regex '^\./[^/]*$' -exec sh -c -- 'for file in "${@}"; do zcat "${file}" || cat "${file}" || exit; done' sh '{}' '+'That assumes you want to interact with files with names like
.hidden.txt.gzthough. If you don’t, and only intend to have a directory with regular files (as opposed to directories or symbolic links or other types of file), using this is much simpler and even safer, and avoids using files in a surprising order:for i in *; do zcat -- "$i" || cat -- "$i" || exit; doneOf course, the real solution is to avoid using the Shell Command Language at all, and to carefully adapt any program to your particular problem as needed: https://sipb.mit.edu/doc/safe-shell/
Yeah, i was tired and had $file there first, then saw that you wanted to cat all in directory. Still tired, but i think this works now.
Thanks !
But still we shouldn’t have to resort to this !
Also, can’t get the output through pipefor i in $(ls); do zcat $i || cat $i; done | grep mysearchtermthis appears to workfind . -type f -print0 | xargs -0 -I{} sh -c 'zcat "{}" 2>/dev/null || cat "{}"' | grep "mysearchterm"Still, that was a speed bump that I guess everyone dealing with mass compressed log files has to figure out on the fly because zcat can’t read uncompressed files ! argg !!!for i in $(ls); do zcat $i 2>/dev/null || cat $i; done | grep mysearchterm
Well, the source code is available. Fix it if you need it that bad.
Where is it? I can’t seen to find it https://github.com/zCat?tab=repositories
It’s part of GNU Gzip, and zcat is basically just a shell script that runs
exec gzip -cd "$@"meaning you can actually just docat /usr/bin/zcatto get the source.
Man, I have a minor inconvenience.
installs Gentoo
Celeste. Are you here? In a future search maybe?
