当たり前だが入ってない

$ aws --version

Command 'aws' not found, but can be installed with:

sudo apt install awscli

以下が入ってるか確認します

/usr/lib/x86_64-linux-gnu/libc.so.6
curl
unzip
groff
less

$ /usr/lib/x86_64-linux-gnu/libc.so.6
GNU C Library (Ubuntu GLIBC 2.31-0ubuntu9.2) stable release version 2.31.
Copyright (C) 2020 Free Software Foundation, Inc.
...以下略

$ curl --version
curl 7.68.0 (x86_64-pc-linux-gnu) libcurl/7.68.0 OpenSSL/1.1.1f zlib/1.2.11 brotli/1.0.7 libidn2/2.2.0 libpsl/0.21.0 (+libidn2/2.2.0) libssh/0.9.3/openssl/zlib nghttp2/1.40.0 librtmp/2.3
...以下略

$ unzip --version

Command 'unzip' not found, but can be installed with:

sudo apt install unzip

$ groff --version
GNU groff version 1.22.4
Copyright (C) 2018 Free Software Foundation, Inc.
...以下略

$ less --version
less 551 (GNU regular expressions)
Copyright (C) 1984-2019  Mark Nudelman
...以下略

unzip 入ってないので入れる

$ sudo apt install unzip
Reading package lists... Done
Building dependency tree
Reading state information... Done
Suggested packages:
  zip
The following NEW packages will be installed:
...などなど以下略

AWS CLIをダウンロード

$ curl "https://awscli.amazonaws.com/awscli-exe-linux-x86_64.zip" -o "/tmp/awscliv2.zip"
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 43.6M  100 43.6M    0     0  6403k      0  0:00:06  0:00:06 --:--:-- 5051k

AWS CLIをインストール

$ unzip /tmp/awscliv2.zip -d /tmp/ && sudo /tmp/aws/install -i /usr/local/aws-cli -b /usr/local/bin
Archive:  /tmp/awscliv2.zip
   creating: /tmp/aws/
   creating: /tmp/aws/dist/
  inflating: /tmp/aws/install
...以下略

確認

aws --version
aws-cli/2.4.21 Python/3.8.8 Linux/4.19.128-microsoft-standard exe/x86_64.ubuntu.20 prompt/off

上手に入りました