Studying Linux commands and frustration

In other words

• I use Linux every day, but I thought there were many commands I didn't know.
• ʻUbuntu 20.04` I wanted to find out about the commands that were included from the beginning.
• I was frustrated.

environment

ʻUbuntu 20.04 is obtained from the Microsoft Store, and after installation, sudo apt updateandsudo apt upgrade` have been performed, and the environment on WSL2.

> cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=20.04
DISTRIB_CODENAME=focal
DISTRIB_DESCRIPTION="Ubuntu 20.04.1 LTS"

command

First, I counted the number of commands (executable files) in the path. (There seems to be different binaries with the same name, but for the time being the same count)

> echo $PATH | sed "s/:/\n/g" | grep -v "^\/mnt" | while read d; do ls -1 "$d"; done | sort | uniq | wc -l
1339

1339 ,, I decided to give up grasping all the commands because it would take several years to remember one command I didn't know each day (Frustration 1).

package

Even if you give up on the command, you still want to know what packages are installed.

> apt list --installed | wc -l
608

608!?. Unreasonable (frustration 2). Therefore, I thought that the packages referenced by various packages would be of high importance because of the package dependencies, so I roughly counted the reverse dependencies of the packages and looked at the ranking.

> apt list --installed | sed "s:\/.*::" | while read p; do n=`apt-cache rdepends "$p" | wc -l`; echo -e "$n\t$p"; done | sort -rn -k1 | head
22107   libc6
6633    libstdc++6
5683    libgcc-s1
4427    perl
3140    libglib2.0-0
2508    zlib1g
2126    python3
1956    libgmp10
1596    libx11-6
1198    dpkg

Libc6 was the top, but when I checked the files extracted by the package with dpkg-query -L libc6, there were only static objects expanded in the lib directory, and there were no bin-related directories. In the first place, many packages starting with lib do not seem to be expanded to the bin directory (excluding libc-bin, libpam-modules-bin, libglib2.0-bin, libcap2-bin, libperl5.30, libpam-runtime). .. Now, let's start with the perl package at the top of the ranking.

> dpkg-query -L perl | grep "bin"
/usr/bin
/usr/bin/corelist
/usr/bin/cpan
/usr/bin/enc2xs
/usr/bin/encguess
/usr/bin/h2ph
/usr/bin/h2xs
/usr/bin/instmodsh
/usr/bin/json_pp
/usr/bin/libnetcfg
/usr/bin/perlbug
/usr/bin/perldoc
/usr/bin/perlivp
/usr/bin/perlthanks
/usr/bin/piconv
/usr/bin/pl2pm
/usr/bin/pod2html
/usr/bin/pod2man
/usr/bin/pod2text
/usr/bin/pod2usage
/usr/bin/podchecker
/usr/bin/podselect
/usr/bin/prove
/usr/bin/ptar
/usr/bin/ptardiff
/usr/bin/ptargrep
/usr/bin/shasum
/usr/bin/splain
/usr/bin/xsubpp
/usr/bin/zipdetails

There are many things I have never seen. I decided to reconsider that it would be okay to learn when it was needed (frustration 3).

from now on

Maybe I should have done it with a little more minimal install. In the first place, I lost track of what I was aiming for. I think it would be better to start by learning the commands contained in the coreutils, bsdutils, and ʻutil-linux` packages.