【M1Mac × Docker】CentOSでlessコマンド使えるようにした話

#前提条件

**OS**
 MacOS Monterey 12.0.1
**CPU**
 Apple M1(arm64) 
**Docker**
Docker Desktop 4.2.0 (70708) 
**CentOS**
CentOS Linux release 7.9.2009 (AltArch)

#やりたいこと

Dockerコンテナで動かすCentOS7で、lessコマンドを使いたい

#つまづいた話

```
[root@0a412e1af0a1 ~]# less -N bunsyo2.txt
bash: less: command not found
```

lessコマンド自体が使えない模様
`bash: less: command not found`

#解決策
yum（※）でlessコマンドをインストール

```
yum install less
```
なんやかんやでインストール成功
（何度か　Is this ok [y/d/N]: と訊かれるので、全てy(Yes)で答えます）

※ -yオプションをつければ、全て「Yes」で答えるものとして進められます

```
[root@0a412e1af0a1 ~]# yum install less
Loaded plugins: fastestmirror, ovl
Determining fastest mirrors
 * base: ftp.yz.yamagata-u.ac.jp
 * extras: ftp.yz.yamagata-u.ac.jp
 * updates: ftp.yz.yamagata-u.ac.jp
base                                                                                                       | 3.6 kB  00:00:00     
extras                                                                                                     | 2.9 kB  00:00:00     
updates                                                                                                    | 2.9 kB  00:00:00     
(1/4): base/7/aarch64/group_gz                                                                             | 153 kB  00:00:00     
(2/4): base/7/aarch64/primary_db                                                                           | 4.9 MB  00:00:02     
(3/4): extras/7/aarch64/primary_db                                                                         | 246 kB  00:00:06     
(4/4): updates/7/aarch64/primary_db                                                                        | 2.1 MB  00:00:07     
Resolving Dependencies
--> Running transaction check
---> Package less.aarch64 0:458-9.el7 will be installed
--> Processing Dependency: groff-base for package: less-458-9.el7.aarch64
--> Running transaction check
---> Package groff-base.aarch64 0:1.22.2-8.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==================================================================================================================================
 Package                         Arch                         Version                             Repository                 Size
==================================================================================================================================
Installing:
 less                            aarch64                      458-9.el7                           base                      115 k
Installing for dependencies:
 groff-base                      aarch64                      1.22.2-8.el7                        base                      920 k

Transaction Summary
==================================================================================================================================
Install  1 Package (+1 Dependent package)

Total download size: 1.0 M
Installed size: 4.1 M
Is this ok [y/d/N]: y
Downloading packages:
warning: /var/cache/yum/aarch64/7/base/packages/groff-base-1.22.2-8.el7.aarch64.rpm: Header V4 RSA/SHA1 Signature, key ID 305d49d6: NOKEY
Public key for groff-base-1.22.2-8.el7.aarch64.rpm is not installed
(1/2): groff-base-1.22.2-8.el7.aarch64.rpm                                                                 | 920 kB  00:00:01     
(2/2): less-458-9.el7.aarch64.rpm                                                                          | 115 kB  00:00:06     
----------------------------------------------------------------------------------------------------------------------------------
Total                                                                                             169 kB/s | 1.0 MB  00:00:06     
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
Importing GPG key 0xF4A80EB5:
 Userid     : "CentOS-7 Key (CentOS 7 Official Signing Key) <security@centos.org>"
 Fingerprint: 6341 ab27 53d7 8a78 a7c2 7bb1 24c6 a8a7 f4a8 0eb5
 Package    : centos-release-7-9.2009.0.el7.centos.aarch64 (@instCentOS)
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
Is this ok [y/N]: y
Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7-aarch64
Importing GPG key 0x305D49D6:
 Userid     : "CentOS AltArch SIG - AArch64 (http://wiki.centos.org/SpecialInterestGroup/AltArch/AArch64) <security@centos.org>"
 Fingerprint: ef8f 3ca6 6efd f32b 36cd adf7 6c7c b6ef 305d 49d6
 Package    : centos-release-7-9.2009.0.el7.centos.aarch64 (@instCentOS)
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7-aarch64
Is this ok [y/N]: y
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : groff-base-1.22.2-8.el7.aarch64                                                                                1/2 
  Installing : less-458-9.el7.aarch64                                                                                         2/2 
  Verifying  : less-458-9.el7.aarch64                                                                                         1/2 
  Verifying  : groff-base-1.22.2-8.el7.aarch64                                                                                2/2 

Installed:
  less.aarch64 0:458-9.el7                                                                                                        

Dependency Installed:
  groff-base.aarch64 0:1.22.2-8.el7                                                                                               

Complete!
```

無事、lessコマンドが使えるようになりました。
もちろん、他に使えないコマンドがあれば、同様の手順で使えるようになります。
（私はコマンドのマニュアルを表示する「manコマンド」も使えなかったので、

```
yum install man
```

で使えるようになりました。）

※補足
yumは
Yellowdog Updater Modified
の略だそうです。

参考ページ

https://qiita.com/taro373/items/fb16c2d214b52abccc3a