37 lines
1.7 KiB
Markdown
37 lines
1.7 KiB
Markdown
# [Day 7](https://adventofcode.com/2022/day/7)
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:gift::gift::gift::gift::gift::gift::gift:
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Today's language: **Bash + Awk**
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Lines of code: **53**
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Execution time: **0,039 s**
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## The protagonist is stupid
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The way the challenge is laid out is absolutely ridiculus; both tasks could be done in one-liners on a Linux machine *(which the device from the challenge probably is)*
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in any POSIX shell,
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*if* the user wasn't as stupid as our protagonist...
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That's why I wrote a bash script that actually creates the whole filesystem from the input-file.
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It does so (by default) in `/tmp`. The sizes for the files are only allocated, so that `du` shows the filesize.
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No actual write operations are taking place, which makes recreating the file structure pretty fast.
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### And so am I?
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The problem is, that (even empty) directories have a size, which also increases with every file and subdirectory in it.
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That's why I needed to calculate the sizes of the directories *without* the actual file sizes and subtract that from the output of `du`.
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This new output can then be piped into an `awk` one-liner. In reality, this problem wouldn't exist since you would want the total size of a directory anyway.
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If the size of the directories themselves would not matter, the commands would be:
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```shell
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# Task 1
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du -b / | awk 'BEGIN{sum=0} {if ($1 <= 100000) {sum+=($1)}} END{print "Total size of all dirs<100000: "sum-0}'
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# Task 2: min_size = (Update size) - (file system size) - (used size)
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du -b / | awk 'BEGIN{file=""; size=99999999} {if ($1 >= min_size && $1 < size) {size=$1; file=$2}} END{print "You should delete "file" size("size")"}'
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```
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## Run today's code
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```shell
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./day7.sh output.txt
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```
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<!-- creates the filesystem -->
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