How to know that you have installed a program on OS X

Since I used Puro,  my MacBook, I get tangled with some app that I don't know wether I have installed it or not. Well, lucky I find some way which is simple yet helpful.
First, check it in your Application folder or you may use "Command+space" then type your apps. If you had installed it, you might have found it.

Second, use terminal, type "which apps_name", it will shows path where you installed it.

bash-3.2# which wget
/usr/local/bin/wget
bash-3.2#

Actually there are another tools like "locate" and "mdfind". But, I can't use locate, there's some errors.



Marias-MacBook-Pro:~ mariabina07$ locate wget

WARNING: The locate database (/var/db/locate.database) does not exist.
To create the database, run the following command:

  sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.locate.plist

Please be aware that the database can take some time to generate; once
the database has been created, this message will no longer appear.

Marias-MacBook-Pro:~ mariabina07$ sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.locate.plist
Password:
com.apple.locate: Already loaded
Marias-MacBook-Pro:~ mariabina07$ locate wget

WARNING: The locate database (/var/db/locate.database) does not exist.
To create the database, run the following command:

  sudo launchctl load -w /System/Library/LaunchDaemons/com.apple.locate.plist

Please be aware that the database can take some time to generate; once
the database has been created, this message will no longer appear.

Marias-MacBook-Pro:~ mariabina07$

So, I can't create the database, and when I used mdfind, It returns many path that contains the keyword.


bash-3.2# mdfind wget
/opt/local/share/doc/automake/ChangeLog
/opt/local/share/man/man3p/File::Fetch-5.12.3pm
/opt/local/share/man/man3p/Config-5.12.3pm
/opt/local/var/macports/sources/rsync.macports.org/release/tarballs/ports/science/rasmol/files/patch-Imakefile.diff
....
/Volumes/Data/Android/android-sdk-macosx/sources/android-14/javax/net/ssl/DefaultHostnameVerifier.java
/Volumes/Data/Master/cocos2d-2.0-x-2.0.3/cocos2dx/platform/third_party/linux/libxml2/libxml/Makefile.in
bash-3.2#


Hope it will helpful in future.. :D