Debian Deep Dive
黒ヰ樹Debian Deep Dive
$ docker run -it debian
で人生変えたと言っても過言ではないぐらいDebianが好きなので完全に理解することにしました。
それでは https://gitlab.com/acefed/gitpod-bash を使用してやっていきます。
2021/02/12 buster-20210208
2021/08/02 buster-20210721
2022/02/05 bullseye-20220125
黒ヰ樹Link
Debian
Debian Manpages
Debian リファレンス（超おすすめ）
DebianとUbuntuの開発用Buildpack
AlpineのDocker
Ubuntuの非開発用Docker
Debianの非開発用Docker（おすすめ）
Memo
※以下本当に.txt上のメモをコピペしただけのもの
ubuntu: xenial bionic focal groovy hirsute
ubuntu: 16.04 18.04 20.04 20.10 21.04
https://wiki.ubuntu.com/Releases
debian: jessie stretch buster bullseye sid
debian: 8 9 10 11 12
https://www.debian.org/releases/
警告 Warning:
注意 Caution:
ヒント Tip:
注記 Note:
TODO:
TODO: binとsbinについて調べる。
TODO: sashやbusybox、alpineあたりで使えるコマンドから調べる。
TODO: diffutils findutils sed gpgv
TODO: openssh-client openssl patch
TODO: https://packages.debian.org/ja/buster/amd64/util-linux/filelist
TODO: more
TODO: invoke-rc.d policy-rc.d update-rc.d
TODO: deb-systemd-helper deb-systemd-invoke service
alpine: ["free", "kill", "pkill", "pgrep", "pmap", "ps", "pwdx", "sysctl", "top", "uptime", "watch", "iostat", "mpstat"]
procps: ["free", "kill", "pkill", "pgrep", "pmap", "ps", "pwdx", "skill", "slabtop", "snice", "sysctl", "tload", "top", "uptime", "vmstat", "w", "watch"]
sysstat: ["sar", "iostat", "tapestat", "mpstat", "pidstat", "sadf", "cifsiostat"]
systemd: ["journalctl", "loginctl", "networkctl", "systemctl", "systemd", "systemd-ask-password", "systemd-escape", "systemd-inhibit", "systemd-machine-id-setup", "systemd-notify", "systemd-sysusers", "systemd-tmpfiles", "systemd-tty-ask-password-agent", "bootctl", "busctl", "hostnamectl", "kernel-install", "localectl", "resolvectl", "systemd-analyze", "systemd-cat", "systemd-cgls", "systemd-cgtop", "systemd-delta", "systemd-detect-virt", "systemd-id128", "systemd-mount", "systemd-path", "systemd-resolve", "systemd-run", "systemd-socket-activate", "systemd-stdio-bridge", "systemd-umount", "timedatectl"]
sudo apt-get update && sudo apt-get install -y --no-install-recommends procps
sudo apt-get update && sudo apt-get install -y --no-install-recommends sysstat
sudo apt-get update && sudo apt-get install -y --no-install-recommends systemd
sudo apt-get update && sudo apt-get install -y --no-install-recommends fdisk
Docker Pull
Gitpodで何も書かなかったらこれをPullしてくる。
$ docker pull gitpod/workspace-full
.gitpod.ymlで明示的に読み込む場合は
image: gitpod/workspace-full
Dockerfileを読んでみると
FROM buildpack-deps:focal
しているのでUbuntuのFocalを使用していることがわかる。
$ docker pull buildpack-deps:focal
buildpack-depsでUbuntuのFocalではなくDebianのBusterを使用するには
$ docker pull buildpack-deps:buster
なのでこれは.gitpod.ymlに書けば
image: buildpack-deps:buster
Gitpod上にないせいか時間がかかるものの問題なく読み込めるらしい。
Dockerfileを読んでみると
FROM debian:buster
しているのでDebianのBusterを使用していることがわかる。
makeなどをapt-getしているDebianがほしいわけではないので.gitpod.ymlにこう書く
image: debian:buster
これを使ってやっていきます。
$ docker pull debian:buster
Docker Pull Memo
buildpack-depsはDebianとUbuntuの開発用Buildpackでプログラミング言語をインストールする際必要になるパッケージがすでにapt-getされている。
nodeの公式イメージなど様々なDockerfileで呼び出されている。
curlはcurlなどを使用してインストールするよう記載があるソフトウェアで使える。
scmはさらにgitなど使用してインストールするよう記載があるソフトウェアで使える。
何も記載がないものは上記含めmakeなど含まれている。
DebianとUbuntuのslimパッケージはOS動かす上で必須ではない/usr/shareに同梱されているドキュメントの一部を取り除き容量を減らしている。
$ docker pull gitpod/workspace-full # focal
$ docker pull gitpod/workspace-full-vnc # focal + etc + vnc
$ docker pull gitpod/workspace-dotnet # focal + etc + dotnet_sdk
$ docker pull gitpod/workspace-dotnet-vnc # focal + etc + vnc + dotnet_sdk
$ docker pull buildpack-deps:buster-curl # curl
$ docker pull buildpack-deps:buster-scm # curl + scm
$ docker pull buildpack-deps:buster # curl + scm + etc
$ docker pull alpine:3.13 # alpine
$ docker pull debian:buster-20210208-slim # Date: 20210208 buster - usr_share
$ docker pull debian:buster-20210208 # Date: 20210208 buster
$ docker pull debian:buster-slim # buster - usr_share
$ docker pull debian:buster # buster
Gitpod Memo
.NETのSDK。
Gitpodは .NET 5.0。VNCでアプリ開発できるが現在はおそらくWindowsアプリのみ。 .NET 6.0でXamarin対応してmacOSとLinuxでも使えるアプリ作れるかもしれない。
Gitpodでは基本的にDebian, Ubuntu, Alpineの公式イメージを使用することを前提に作られている。
が一応Amazon LinuxとLinux Mintも使用できるらしい。
問題なく動くか不明なのでおすすめはしない。
黒ヰ樹1
image: debian:buster
tasks:
- command: bash command.sh
#!/bin/bash
echo "Hello, World!"
Gitpod起動後すぐにBashコマンドをしてくれます。
$ bash command.sh
Hello, World!
2
$ echo $PATH
パスが表示されました。OSでは基本的にこのディレクトリにあるコマンドを使用できます。
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
# null
$ ls -R /usr/local/sbin
$ ls -R /usr/local/bin
$ ls -R /usr/sbin
$ ls -R /usr/bin
$ ls -R /sbin
$ ls -R /bin
[
"add-shell","addgroup","adduser","chgpasswd","chmem","chpasswd","chroot","cpgr","cppw","delgroup","deluser","dpkg-fsys-usrunmess","dpkg-preconfigure","dpkg-reconfigure","e2freefrag","e4crypt","e4defrag","faillock","fdformat","filefrag","groupadd","groupdel","groupmems","groupmod","grpck","grpconv","grpunconv","iconvconfig","invoke-rc.d","ldattach","mklost+found","newusers","nologin","pam-auth-update","pam_getenv","pam_timestamp_check","policy-rc.d","pwck","pwconv","pwunconv","readprofile","remove-shell","rmt","rmt-tar","rtcwake","service","tarcat","tzconfig","update-passwd","update-rc.d","useradd","userdel","usermod","vigr","vipw","zic",
"addpart","apt","apt-cache","apt-cdrom","apt-config","apt-get","apt-key","apt-mark","arch","awk","b2sum","base32","base64","basename","basenc","bashbug","captoinfo","catchsegv","chage","chattr","chcon","chfn","choom","chrt","chsh","cksum","clear","clear_console","cmp","comm","csplit","cut","deb-systemd-helper","deb-systemd-invoke","debconf","debconf-apt-progress","debconf-communicate","debconf-copydb","debconf-escape","debconf-set-selections","debconf-show","delpart","diff","diff3","dircolors","dirname","dpkg","dpkg-deb","dpkg-divert","dpkg-maintscript-helper","dpkg-query","dpkg-realpath","dpkg-split","dpkg-statoverride","dpkg-trigger","du","env","expand","expiry","expr",
"factor","faillog","fallocate","fincore","find","flock","fmt","fold","getconf","getent","getopt","gpasswd","gpgv","groups","head","hostid","i386","iconv","id","infocmp","infotocap","install","ionice","ipcmk","ipcrm","ipcs","ischroot","join","last","lastb","lastlog","ldd","link","linux32","linux64","locale","localedef","logger","logname","lsattr","lscpu","lsipc","lslocks","lslogins","lsmem","lsns","mawk","mcookie","md5sum","md5sum.textutils","mesg","mkfifo","namei","nawk","newgrp","nice","nl","nohup","nproc","nsenter","numfmt","od","pager","partx","passwd","paste","pathchk","perl","perl5.32.1","pinky","pldd","pr","printenv","printf","prlimit","ptx",
"realpath","renice","reset","resizepart","rev","rgrep","runcon","savelog","script","scriptlive","scriptreplay","sdiff","seq","setarch","setpriv","setsid","setterm","sg","sha1sum","sha224sum","sha256sum","sha384sum","sha512sum","shred","shuf","sort","split","stat","stdbuf","sum","tabs","tac","tail","taskset","tee","test","tic","timeout","toe","touch","tput","tr","truncate","tset","tsort","tty","tzselect","unexpand","uniq","unlink","unshare","update-alternatives","users","utmpdump","wall","wc","whereis","which","who","whoami","x86_64","xargs","yes","zdump",
"agetty","badblocks","blkdiscard","blkid","blkzone","blockdev","chcpu","ctrlaltdel","debugfs","dumpe2fs","e2fsck","e2image","e2label","e2mmpstatus","e2scrub","e2scrub_all","e2undo","findfs","fsck","fsck.cramfs","fsck.ext2","fsck.ext3","fsck.ext4","fsck.minix","fsfreeze","fstab-decode","fstrim","getty","hwclock","installkernel","isosize","killall5","ldconfig","logsave","losetup","mke2fs","mkfs","mkfs.bfs","mkfs.cramfs","mkfs.ext2","mkfs.ext3","mkfs.ext4","mkfs.minix","mkhomedir_helper","mkswap","pivot_root","raw","resize2fs","runuser","shadowconfig","start-stop-daemon","sulogin","swaplabel","swapoff","swapon","switch_root","tune2fs","unix_chkpwd","unix_update","wipefs","zramctl",
"bash","cat","chgrp","chmod","chown","cp","dash","date","dd","df","dir","dmesg","dnsdomainname","domainname","echo","egrep","false","fgrep","findmnt","grep","gunzip","gzexe","gzip","hostname","ln","login","ls","lsblk","mkdir","mknod","mktemp","more","mount","mountpoint","mv","nisdomainname","pidof","pwd","rbash","readlink","rm","rmdir","run-parts","sed","sh","sleep","stty","su","sync","tar","tempfile","touch","true","umount","uname","uncompress","vdir","wdctl","ypdomainname","zcat","zcmp","zdiff","zegrep","zfgrep","zforce","zgrep","zless","zmore","znew"
]
とりあえずcdコマンドで移動してみる。
/$ cd home
/home$ cd ..
/$ cd home
/home$ cd ~
/$ cd home
/home$ cd -
/$
3
$ bash --help
GNU bash, version 5.1.4(1)-release-(x86_64-pc-linux-gnu)
...
Bashの組み込みコマンドを確認できる方法が記載されているので試してみる。
$ bash -c help
cdなど新たにコマンドを確認できた。
[
"case","do","done","elif","else","esac","fi","for","function","if","in","select","then","until","while","time",
"alias","bg","bind","break","builtin","caller","cd","command","compgen","complete","compopt","continue","coproc","declare","dirs","disown","echo","enable","eval","exec","exit","export",
"false","fc","fg","getopts","hash","help","history","jobs","kill","let","local","logout","mapfile","popd","printf","pushd","pwd","read","readarray","readonly","return",
"set","shift","shopt","source","suspend","test","times","trap","true","type","typeset","ulimit","umask","unalias","unset","variables","wait"
]
上記コマンドは$ helpで確認できるものと同じです。
環境変数一覧。
$ export
$を押した後にTabキー2回押して表示できる環境変数一覧と分けてみた。
[
"HOME","HOSTNAME","OLDPWD","PATH","PWD","SHLVL","TERM",
"BASH","BASHOPTS","BASHPID","BASH_ALIASES","BASH_ARGC","BASH_ARGV","BASH_ARGV0","BASH_CMDS","BASH_COMMAND","BASH_LINENO","BASH_SOURCE","BASH_SUBSHELL","BASH_VERSINFO","BASH_VERSION",
"COLUMNS","COMP_WORDBREAKS","DIRSTACK","EPOCHREALTIME","EPOCHSECONDS","EUID","GROUPS","HISTCMD","HISTFILE","HISTFILESIZE","HISTSIZE","HOSTTYPE","IFS","LINENO","LINES",
"MACHTYPE","MAILCHECK","OPTERR","OPTIND","OSTYPE","PIPESTATUS","PPID","PS1","PS2","PS4","RANDOM","SECONDS","SHELL","SHELLOPTS","SRANDOM","UID","_"
]
組み込みコマンドtypeでcdとcat、archの切り分けをしてみましょう。
$ type arch
arch is /usr/bin/arch
$ type cat
cat is /bin/cat
$ type cd
cd is a shell builtin
ほぼ全ての使用できるコマンドを把握できたのでようやく楽しめそうです。
3 Memo
ライブラリ用パスの確認
$ ls /etc/ld.so.conf.d/
libc.conf x86_64-linux-gnu.conf
$ cat /etc/ld.so.conf.d/libc.conf
# libc default configuration
/usr/local/lib
$ cat /etc/ld.so.conf.d/x86_64-linux-gnu.conf
# Multiarch support
/usr/local/lib/x86_64-linux-gnu
/lib/x86_64-linux-gnu
/usr/lib/x86_64-linux-gnu
# null
$ /usr/local/lib
$ ls /usr/local/lib/x86_64-linux-gnu
$ ls /usr/lib/x86_64-linux-gnu
$ ls /lib/x86_64-linux-gnu
[
"libacl.so.1","libacl.so.1.1.2253","libapt-pkg.so.6.0","libapt-pkg.so.6.0.0","libapt-private.so.0.0","libapt-private.so.0.0.0","libattr.so.1","libattr.so.1.1.2448","libblkid.so.1","libblkid.so.1.1.0","libcrypto.so.1.1","libdb-5.3.so","libdebconfclient.so.0","libdebconfclient.so.0.0.0","libffi.so.7","libffi.so.7.1.0","libgcrypt.so.20","libgcrypt.so.20.2.8","libgmp.so.10","libgmp.so.10.4.1","libgnutls.so.30","libgnutls.so.30.29.1","libgssapi_krb5.so.2","libgssapi_krb5.so.2.2",
"libhogweed.so.6","libhogweed.so.6.4","libidn2.so.0","libidn2.so.0.3.7","libk5crypto.so.3","libk5crypto.so.3.1","libkrb5.so.3","libkrb5.so.3.3","libkrb5support.so.0","libkrb5support.so.0.1","liblz4.so.1","liblz4.so.1.9.3","libmount.so.1","libmount.so.1.1.0","libnettle.so.8","libnettle.so.8.4","libnsl.so.2","libnsl.so.2.0.1","libp11-kit.so.0","libp11-kit.so.0.3.0","libpcre2-8.so.0","libpcre2-8.so.0.10.1","libpcreposix.so.3","libpcreposix.so.3.13.3",
"libseccomp.so.2","libseccomp.so.2.5.1","libsemanage.so.1","libsmartcols.so.1","libsmartcols.so.1.1.0","libssl.so.1.1","libstdc++.so.6","libstdc++.so.6.0.28","libsystemd.so.0","libsystemd.so.0.30.0","libtasn1.so.6","libtasn1.so.6.6.0","libtic.so.6","libtic.so.6.2","libudev.so.1","libudev.so.1.7.0","libunistring.so.2","libunistring.so.2.1.0","libuuid.so.1","libuuid.so.1.3.0","libxxhash.so.0","libxxhash.so.0.8.0","libzstd.so.1","libzstd.so.1.4.8",
"audit","e2fsprogs","engines-1.1","gconv","krb5","perl-base",
"ld-linux-x86-64.so.2","libBrokenLocale-2.31.so","libBrokenLocale.so.1","libSegFault.so","libanl-2.31.so","libanl.so.1","libaudit.so.1","libaudit.so.1.0.0","libbz2.so.1","libbz2.so.1.0","libbz2.so.1.0.4","libc.so.6","libcap-ng.so.0","libcap-ng.so.0.0.0","libcom_err.so.2","libcom_err.so.2.1","libcrypt.so.1","libcrypt.so.1.1.0","libdl-2.31.so","libdl.so.2","libe2p.so.2","libe2p.so.2.3","libext2fs.so.2","libext2fs.so.2.4","libgcc_s.so.1","libgpg-error.so.0","libgpg-error.so.0.29.0","libkeyutils.so.1","libkeyutils.so.1.9",
"liblzma.so.5","liblzma.so.5.2.5","libm-2.31.so","libm.so.6","libmemusage.so","libmvec-2.31.so","libmvec.so.1","libnsl-2.31.so","libnsl.so.1","libnss_compat-2.31.so","libnss_compat.so.2","libnss_dns-2.31.so","libnss_dns.so.2","libnss_files-2.31.so","libnss_files.so.2","libnss_hesiod-2.31.so","libnss_hesiod.so.2","libpam.so.0","libpam.so.0.85.1","libpam_misc.so.0","libpam_misc.so.0.82.1","libpamc.so.0","libpamc.so.0.82.1","libpcprofile.so","libpcre.so.3","libpcre.so.3.13.3","libpthread.so.0",
"libresolv-2.31.so","libresolv.so.2","librt-2.31.so","librt.so.1","libselinux.so.1","libsepol.so.1","libss.so.2","libss.so.2.0","libthread_db-1.0.so","libthread_db.so.1","libtinfo.so.6","libtinfo.so.6.2","libtirpc.so.3","libtirpc.so.3.0.0","libutil-2.31.so","libutil.so.1","libz.so.1","libz.so.1.2.11",
"ld-2.31.so","libc-2.31.so","libpthread-2.31.so",
"security"
]
BashではなくDashが紐付いており一部コマンドが使用できない可能性があるのでそういった場合は上記manページで確認してください。
なんとなくdashと入力しターミナルが壊れた場合は
$ bash
を試してみたら直るかも。
ちなみにAlpineはBashのほかBusyBoxのAshが入っています。
bash => Bash => Bourne Again Shell
dash => Dash => Debian Almquist shell
ash => Ash => Almquist Shell
黒ヰ樹4
/dev/nullあるか確認してなかったので確認しておく。
$ ls /dev
console core fd full mqueue null ptmx pts random shm stderr stdin stdout tty urandom zero
まずはcatコマンドでファイルの表示。せっかくなのでOS情報を確認してみます。
$ cat /etc/os-release
PRETTY_NAME="Debian GNU/Linux 11 (bullseye)"
NAME="Debian GNU/Linux"
VERSION_ID="11"
VERSION="11 (bullseye)"
VERSION_CODENAME=bullseye
ID=debian
HOME_URL="https://www.debian.org/"
SUPPORT_URL="https://www.debian.org/support"
BUG_REPORT_URL="https://bugs.debian.org/"
Debian GNU/Linux 10 (buster)で間違いないことがわかりました。
odコマンドで表示してみましょう。
$ od -ta /etc/os-release
0000000 P R E T T Y _ N A M E = " D e b
0000020 i a n sp G N U / L i n u x sp 1 1
0000040 sp ( b u l l s e y e ) " nl N A M
0000060 E = " D e b i a n sp G N U / L i
0000100 n u x " nl V E R S I O N _ I D =
0000120 " 1 1 " nl V E R S I O N = " 1 1
0000140 sp ( b u l l s e y e ) " nl V E R
0000160 S I O N _ C O D E N A M E = b u
0000200 l l s e y e nl I D = d e b i a n
0000220 nl H O M E _ U R L = " h t t p s
0000240 : / / w w w . d e b i a n . o r
0000260 g / " nl S U P P O R T _ U R L =
0000300 " h t t p s : / / w w w . d e b
0000320 i a n . o r g / s u p p o r t "
0000340 nl B U G _ R E P O R T _ U R L =
0000360 " h t t p s : / / b u g s . d e
0000400 b i a n . o r g / " nl
0000413
spはスペース、nlは改行。
AWKでHello, World!
$ awk 'BEGIN { print "Hello, World!" }'
Hello, World!
PerlでHello, World!
$ perl -e 'print "Hello, World!\n";'
Hello, World!
4.1
今回はパッケージを一切追加しないが忘備録として書いておく。
root権限があればパッケージを追加できる。BusyBoxを追加する場合は以下の通り。
$ apt-get update && apt-get install busybox
-y --no-install-recommendsオプションをつけることでRecommended packagesを除いた最も少ないパッケージをインストールすることが出来る。
-y --install-suggestsオプションをつけることでSuggested packagesを含めた最も多いパッケージをインストールすることが出来る。
$ apt-get update && apt-get install busybox
...
Reading package lists... Done
ここまでがapt-get updateの処理。
Reading package lists... Done
...
Setting up busybox (1:1.30.1-6+b3) ...
ここまでがapt-get install busyboxの処理。
vimを使ってみる。emacsやnanoは入ってない。viでも同じものを呼び出せる。
$ vim --help
VIM - Vi IMproved 8.2 (2019 Dec 12, compiled Oct 01 2021 01:51:08)
...
起動
$ vim
iキーを押したあとHello, World!と入力。
ちゃんと入力されたことを確認したらEscキーを押す。
:を押したあとにw abc.txtと入力。
:w abc.txt
問題なく保存できた。
vim上でコマンドも試しておく。
:!echo 127
vimの終了。
:q
間違って追記してしまい保存せず終了する場合は
:qa!
一安心。
Gitpod上のDebianで起動したvim
Gitpod上のAlpineで起動したvi
$ less /etc/os-release
テキストビューア。ターミナルログとは別途起動してくれる。
ただmoreコマンドと異なり全て読み終えても自動的に終了しないため終了するときはqキーを押す。
黒ヰ樹5
$ mkdir xyz
ディレクトリを作成する。
$ dpkg -l > xyz/00.txt
パッケージ一覧をファイルに標準出力する。
パッケージ追加した後複数ファイル出力しておきdiffコマンドを使うと何を入れたか把握しやすくなる。
$ more xyz/00.txt
簡易的なテキストビューア。
catコマンドと異なり1画面ずつ表示してくれる。
$ gzip -k xyz/00.txt
ファイルを圧縮するコマンド。ディレクトリはできない。
-kオプションで元のファイル00.txtが保持され、00.txt.gzファイルがあらたにできる。
$ gunzip -l xyz/00.txt.gz
compressed uncompressed ratio uncompressed_name
4128 15231 73.1% xyz/00.txt
展開しても元ファイルに上書きされるだけなので-lオプションで圧縮率の確認をしておく。
なかなかの圧縮率を誇ることがわかった。
$ tar -cvzf xyz.tar.gz xyz
ディレクトリの圧縮、展開もできるコマンド。
-cオプションでtarアーカイブして-zオプションでgzip圧縮している。
$ tar -tf xyz.tar.gz
xyz/
xyz/00.txt.gz
xyz/00.txt
展開しても元ディレクトリに上書きされるだけなので-tオプションでアーカイブ中身の確認をしておく。
またxyz/00.txt.gzのようなgzip圧縮されているテキストファイルは展開しなくても$ zcatコマンドで読むことができる。
gzipパッケージに同梱されているファイル一覧はインターネットで調べたほうが早いと思う。
amd64であるかどうかは$dpkg -lのArchitectureを確認するか
$ arch
でサーバーのアーキテクチャを表示できる。
x86_64はamd64である。
またアーキテクチャ、パッケージをはじめとしたDocker公式イメージの詳細については以下のページで確認できる。
少し重いので注意。
黒ヰ樹6
先程確認した$ archのヘルプを表示してみよう。
$ arch --help
Usage: arch [OPTION]...
Print machine architecture.
--help display this help and exit
--version output version information and exit
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>
Full documentation <https://www.gnu.org/software/coreutils/arch>
or available locally via: info '(coreutils) arch invocation'
どうやらcoreutilsに含まれるコマンドらしい。
せっかくなのでdpkgからgrepコマンドで検索してみることにする。
$ dpkg -l | grep coreutils
ii coreutils 8.32-4+b1 amd64 GNU core utilities
パイプ|を使用しdpkgコマンドで出力した内容をgrepコマンドに渡して検索することができた。
GNU core utilitiesと呼ばれるパッケージを使用しているらしい。
今までいくつか出てきたコマンド、例えばlsやcatも同様にGNU core utilitiesから提供されているもので、非常に多くのLinuxで使用されている自由なソフトウェアである。ありがとうRMS。
なので大量のコマンドがありどれを覚えたらいいか分からない場合まずはGNU core utilitiesのマニュアルで確認できるコマンドから始めたらいいかもしれない。
もちろんBashなどで使われている組み込みコマンドechoやcdも同じぐらい重要ですが。
マニュアルは拡張子html, txt, pdf, html.gz, txt.gz, dvi.gz, tar.gz, texi.tar.gzで提供しているのでスマホでhtml見づらかったらpdf、txtの容量が大きいときは圧縮されたtxt.gzファイルをgzipに含まれるテキストビューアで読むといいかも。
coreutilsのほか今まで紹介してきたbash, grep, gzip, tarのほか、後日紹介するsedやdiffなどもGNUパッケージである。ありがとうFSF。
ちなみにDebianに同梱されているAWKはgawkではなくmawkです。