软件操作命令：
软件包管理器：yum
安装软件：yum install xxx
卸载软件： yum remove xxx
搜索软件： yum serach xxx
清理软件： yum clean packages
列出已安装： yum list
软件包信息： yum info xxx
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Type `help' to learn how to use Xshell prompt.
[c:~]$ help
Internal Commands:
new: Creates a new session.
open: Opens a session or the session dialog box.
edit: Opens the Session Property dialog box for a session.
list: Lists information of all available sessions.
cd: Changes the current working directory.
pwd: Shows the current working directory.
set: Sets options.
clear: Clears the screen/address/command history.
help: Displays this help. '?' does the same.
quit: Quits Local Shell. 'exit' does the same.
ssh: Connects to a host using the SSH protocol.
telnet: Connects to a host using the TELNET protocol.
rlogin: Connects to a host using the RLOGIN protocol.
sftp: Connects to a host to transfer files securely.
ftp: Connects to a host to transfer files.
disconnect: Closes connection of this session.
reconnect: Reconnects this session.
For more information, type 'help command' for each command.
ex) help telnet
[c:~]$
