What is Bash completion?
Bash completion is a functionality through which Bash helps users type their commands more quickly and easily. It does this by presenting possible options when users press the Tab key while typing a command.
reference: https://opensource.com/article/18/3/creating-bash-completion-script
先查詢是否有安裝 bash-completion
$ rpm -qi bash-completion
# package bash-completion is not installed確定沒有這個軟體，那就開始進行安裝。
安裝 bash-completion
$ sudo yum -y install bash-completion bash-completion-extras
# Loaded plugins: fastestmirror
# Loading mirror speeds from cached hostfile
# epel/x86_64/metalink | 9.0 kB 00:00:00
# * base: ftp.tc.edu.tw
# * epel: fedora.cs.nctu.edu.tw
# * extras: ftp.tc.edu.tw
# * updates: ftp.tc.edu.tw
# base | 3.6 kB 00:00:00
# extras | 2.9 kB 00:00:00
# updates | 2.9 kB 00:00:00
# updates/7/x86_64/primary_db | 5.8 MB 00:00:00
# Resolving Dependencies
# --> Running transaction check
# ---> Package bash-completion.noarch 1:2.1-6.el7 will be installed
# ---> Package bash-completion-extras.noarch 1:2.1-11.el7 will be installed
# --> Finished Dependency Resolution
#
# Dependencies Resolved
#
# ===============================================================================================================================================================
# Package Arch Version Repository Size
# ===============================================================================================================================================================
# Installing:
# bash-completion noarch 1:2.1-6.el7 base 85 k
# bash-completion-extras noarch 1:2.1-11.el7 epel 123 k
#
# Transaction Summary
# ===============================================================================================================================================================
# Install 2 Packages
#
# Total download size: 208 k
# Installed size: 648 k
# Is this ok [y/d/N]: y
# Downloading packages:
# (1/2): bash-completion-2.1-6.el7.noarch.rpm | 85 kB 00:00:00
# (2/2): bash-completion-extras-2.1-11.el7.noarch.rpm | 123 kB 00:00:00
# ---------------------------------------------------------------------------------------------------------------------------------------------------------------
# Total 225 kB/s | 208 kB 00:00:00
# Running transaction check
# Running transaction test
# Transaction test succeeded
# Running transaction
# Installing : 1:bash-completion-2.1-6.el7.noarch 1/2
# Installing : 1:bash-completion-extras-2.1-11.el7.noarch 2/2
# Verifying : 1:bash-completion-extras-2.1-11.el7.noarch 1/2
# Verifying : 1:bash-completion-2.1-6.el7.noarch 2/2
#
# Installed:
# bash-completion.noarch 1:2.1-6.el7
# bash-completion-extras.noarch 1:2.1-11.el7
#
# Complete!重新登入
登出再登入系統後，就能使用了