bew ​Jun 20
Julia Evans

here's the final version of the "redirects cheat sheet" draft I posted a while back!

("The Secret Rules of the Terminal" is finished! 95 beta readers have read it! the copy editor is done! technical review is done! the illustrator has made the cover! It's going to be out on *****Tuesday June 24*****")

Jun 20 at 7:50pmWeb
Show threadJulia EvansJun 20
95 beta readers is a new record, I used to ask maybe 1-2 people to read a zine before it went out but this one went through 4 rounds of beta readers who made it a LOT better than it started
Show threadPhilip GuoJun 20
@b0rk yay for playtesting for zines!
Show threadArne MertzJun 20
@b0rk it was a fun read, looking forward to the finished version
Show threadChris MarkiewiczJun 20
@b0rk Nice! I always forget how to do the stderr redirects... For gotcha 1, have you seen `sponge` from moreutils? https://joeyh.name/code/moreutils/
moreutils

Show threadJulia EvansJun 20
@effigies yeah it seems very reasonable! i have a rule about not including tools that I have never personally used though, it's too hard for me to evaluate/recommend them
Show threadDavidJun 22

@effigies @b0rk
Is sponge very different from tee? Man page makes it sound like it doesn't print its input but sounds same otherwise?

Must admit, I'm not sure if `cat file | tee file` would delete the file.

Show threadJulia EvansJun 23
@idbrii @effigies this stack overflow answer gives an example where tee and sponge have different results https://stackoverflow.com/questions/33638511/differences-between-sponge-and-tee/68606136#68606136
Show threadBlue LumaJun 20
@b0rk having to remember what 0, 1 and 2 mean doesnnt make sens. That's why I like the approach nushell took with letters https://www.nushell.sh/lang-guide/chapters/pipelines.html
Pipelines | Nushell

A new type of shell.

Show threadJulia EvansJun 20
@blueluma that's a cool idea
Show threadLéanaJun 20
@b0rk I would like to mention that `:> file.txt` is the same as `touch file.txt` in the sense that it creates an empty file. Pretty cool.
Maybe I have learned this from Veronica Explains but I'm not sure.
Show threadMichielJun 21
@IndigoPRNG @b0rk : is a no-op, so it’s a cool use of this.
Show threadPhilip GuoJun 20
@b0rk is there a way to order now online?
Show threadPhilip GuoJun 20
@b0rk and will it be included in the 'full pack' of all zines? i can probably order full set of printed copies thru school in the future for teaching, etc.
Show threadJulia EvansJun 20
@pg it will! you can't order it until Tuesday though
Show threadPhilip GuoJun 21
@b0rk great, i may order a set for myself first to check it out, i always appreciate printed materials
Show threadlispwizardJun 20

@b0rk I am fond of <(do some command) which bash and some other shells support. As an example, after have gzipped and split a large file (e.g. a .iso) onto a cd or dvd, you can make sure the result of the gzip'ed splitting matches the original with

cmp foo.iso <(cat splitfoo* | gzip -cd -)

(I know that final - isn't necessary, but I like to make it explicit.)

Show threadmei | 絶望動物Jun 20
@b0rk huh, which shells do &|? bash does |&, and it kinda feels like the canonical implementation 😅
Show threadJulia EvansJun 20
@mei fish
Show threadmei | 絶望動物Jun 21
@b0rk ah, the usual suspect!
Show threadOlivier MehaniJun 21

@b0rk One thing that confuses people is the combination with user permissions.

```
sudo cat ~/allowed_file > /root
```

doesn't work because the user's shell runs the `>` redirection, and it doesn't have permissions to write to `/root`. The `sudo` part is useless, as the user is allowed to read the file anyway.

Instead, the output needs to be piped into a tool running as the appropriate user.

I tend to use `tee` for that. It's main purpose is to duplicate a stream to both 1) stdout and 2) a file, but here, we want 2), run as root.

```
cat ~/allowed_file | sudo tee /root >/dev/null
```

The redirection is for the output from 1), as it's not needed here.

Show threadMichielJun 21
@b0rk &> is not POSIX though. If you’re on a minimal system with /bin//sh only your script will not work
Show threadSamuel BucquetJun 21
@b0rk hi, process substitution (https://mywiki.wooledge.org/ProcessSubstitution) is a great tool in the same family, e.g. :
```
diff <(sort list1) <(sort list2)
```