如果你不知道完成某個特定任務所需要命令的名稱，可以使用一個關鍵字通過Linux apropos實用程序來搜索它。該實用程序可以搜索關鍵字並且顯示所有包含匹配項的man頁面的簡短描述。另外，使用man實用程序和-k（關鍵字）選項，可以得到和用Linux apropos實用程序相同的結果（實際上是相同的命令）。
以下是Linux apropos命令列表：
- [root@localhost ~]# man -k who
- at.allow [at] (5) - determine who can submit jobs via at or batch
- at.deny [at] (5) - determine who can submit jobs via at or batch
- jwhois (1) - client for the whois service
- jwhois (rpm) - Internet whois/nicname client.
- Net::LDAP::Extension::WhoAmI (3pm) - LDAP Who am I? Operation
- w (1) - Show who is logged on and what they are doing
- who (1p) - display who is on the system
- who (1) - show who is logged on
- whoami (1) - print effective userid
- [root@localhost ~]# apropos who
- at.allow [at] (5) - determine who can submit jobs via at or batch
- at.deny [at] (5) - determine who can submit jobs via at or batch
- jwhois (1) - client for the whois service
- jwhois (rpm) - Internet whois/nicname client.
- Net::LDAP::Extension::WhoAmI (3pm) - LDAP Who am I? Operation
- w (1) - Show who is logged on and what they are doing
- who (1p) - display who is on the system
- who (1) - show who is logged on
- whoami (1) - print effective userid