用whereis命令查找:
比如查找是否安装了Gedit:
math@Chang:~$ whereis gedit
gedit: /usr/bin/gedit /usr/share/man/man1/gedit.1.gz //安装了
math@Chang:~$ whereis apache
apache: //未安装
或者使用whatis
math@Chang:~$ whatis gedit
gedit (1) - text editor for the GNOME Desktop
math@Chang:~$ whatis samba
samba (7) - A Windows SMB/CIFS fileserver for UNIX