As an aside, a friend of mine has already arranged (as a joke) the rights to compile and remix any bash snippets I post in chat groups in a blog or book. Maybe I should write more about this, but then, it's probably most helpful exactly because I just drop it in places rather than writing a comprehensive work that nobody sits down to read. Still, I'm curious what the syntax/feature/pattern is that you found useful :)
Personally, I didn't know about the
(
... commands ...
) > some_file.txt
syntax. Like, I knew about file redirection, but I didn't know you could group commands like that and redirect all their output with one operator. I would have had to do a bunch of appending with `>>`
Three tools that I think are less widely known compared to how useful they are: jq, progress, and pv.
`pv` (pipe view) is rather simple but I use it for viewing a lot and sometimes rate-limiting transfers. Usage is simple: `curl huge-file | pv | some-operation` will show you the progress (okay, curl already does... but pv works for any pipe input, and pv can work in line mode with -l so you can see how many lines (records, presumably) it processed).
`progress` is even simpler! Just type progress in a random terminal while, in another, you are running an operation like cp, gzip, etc.
Use -m to monitor instead of doing a one-shot. This will also allow it to calculate the remaining time (for anything running at more than a few kilobytes per second).
I also love progress just because it's such a hack. It hooks into the process and monitors file operations. Simple but effective. Somehow it works super well because it manages to ignore everything irrelevant and only shows you the file handle you care about (you can give it hints if necessary, I've used that maybe once in ten years).
`jq` takes JSON data and either pretty-prints (default) or operates on it:
$ echo '{"whoami": "root"}' | jq
{
"whoami": "root"
}
# imagine colored output above
$ echo '{"whoami": "root"}' | jq .whoami
"root"
$ echo '{"users": [{"name": "abc", ...}, ...]}' | jq '.users[].name'
# prints the name of all users in this array
$ curl localhost/api/v1/users | jq '.users[] | "\(.name) \(.age)"' | sort -n -k 2 | tail -1 && echo "is our oldest user!"
Hey I just get enthusiastic about bash and commandline in general as these tools have saved my hours of work compared to using gui
And I love your enthusiasm in the comment and things you just taught me today.
I’m definitely going to take a note of this and add to my TIL Notes so I can always refer back to this
I just wanted to thank you for teaching me something totally new today
Consider adding zsh and Perl to your toolbelt. Many scripting languages are just as powerful as Perl, but I don't know of anything that has equivalent capability for quick work on the CLI. Check out how the `-pi -E` switches work, for an example: https://perldoc.perl.org/perlrun#-i%5Bextension%5D
Also, jq is amazing and is basically sed for json data.
As an aside, a friend of mine has already arranged (as a joke) the rights to compile and remix any bash snippets I post in chat groups in a blog or book. Maybe I should write more about this, but then, it's probably most helpful exactly because I just drop it in places rather than writing a comprehensive work that nobody sits down to read. Still, I'm curious what the syntax/feature/pattern is that you found useful :)