find功能最強的查找文件命令
-size 按文件大小查找，第一個參數為查詢目錄
可以不寫查詢目錄，默認從當前所在目錄遞歸查找：
mcdx@ubuntu:~$ sudo find /etc -size +333k
/etc/apparmor.d/cache/usr.bin.evince
/etc/brltty/Contraction/zh-tw-ucb.ctb
/etc/brltty/Contraction/zh-tw.ctb
mcdx@ubuntu:~$ cd /etc
mcdx@ubuntu:/etc$ sudo find -size +333k
./apparmor.d/cache/usr.bin.evince
./brltty/Contraction/zh-tw-ucb.ctb
./brltty/Contraction/zh-tw.ctb
-name 按照文件名查找，-iname 忽略大小寫，參數可接受通配符
* 任意數量任意字符
? 0 個或 1 個任意字符
[asdf] 字符集，類似正則里的概念，匹配任意一個里面包含的字符
舉個例子：
mcdx@ubuntu:~$ find test -name '*.py'
test/shiyan/shiyan/middlewares.py
test/shiyan/shiyan/pipelines.py
test/shiyan/shiyan/items.py
test/shiyan/shiyan/settings.py
test/shiyan/shiyan/__init__.py
test/shiyan/shiyan/spiders/image.py
test/shiyan/shiyan/spiders/haha.py
test/shiyan/shiyan/spiders/__init__.py
mcdx@ubuntu:~$ find git/pc -name app.py
git/pc/37_代碼框架及數據庫設計/jobplus/jobplus/app.py
git/pc/29_增加用戶頁面/simpledu/simpledu/app.py
git/pc/38_首頁和注冊登錄功能/jobplus/jobplus/app.py
git/pc/08_為文章增加標簽/news/app.py
git/pc/07_從數據庫中讀取內容/news/app.py
git/pc/06_一個簡單的資訊網站/news/app.py
對軟鏈接的查找用 -lname，對硬鏈接的查找用 -samefile，查找節點號用 -inum ：
mcdx@ubuntu:~/test$ ll -i
總用量 12
1460981 drwxrwxr-x 3 mcdx mcdx 4096 Jul 19 10:29 ./
1485401 drwxr-xr-x 20 mcdx mcdx 4096 Jul 19 08:59 ../
1494630 -rw-rw-r-- 1 mcdx mcdx 0 Jul 13 17:33 0001.c
1495120 -rw-rw-r-- 1 mcdx mcdx 0 Jul 13 17:33 0002.c09
1495232 -rw-rw-r-- 1 mcdx mcdx 0 Jul 13 17:33 0003.c
1483901 -rw-rw-r-- 3 mcdx mcdx 0 Jul 19 10:29 a
1483901 -rw-rw-r-- 3 mcdx mcdx 0 Jul 19 10:29 a1
1483901 -rw-rw-r-- 3 mcdx mcdx 0 Jul 19 10:29 a2
1472327 drwxr-sr-x 3 mcdx mcdx 4096 Jun 8 10:00 shiyan/
mcdx@ubuntu:~/test$ find -inum 1483901
./a
./a1
./a2
-links 查找指定鏈接數的文件：
mcdx@ubuntu:~/test$ find -links 3
.
./shiyan
./shiyan/shiyan/image
./a
./a1
./a2
-exec 對查詢結果進一步操作，格式：find [條件] [參數] -exec [命令] {} \;
Mcdx@haha~$ find . -size +111M
./Library/Caches/com.apple.helpd/SDMHelpData/AppleMain/zh_CN/lsm_map
./Library/Caches/com.apple.helpd/SDMHelpData/Other/zh_CN/lsm_map
./Library/Caches/com.apple.helpd/SDMHelpData/AppleExtra/zh_CN/lsm_map
Mcdx@haha~$ find . -size +111M -exec ls -l {} \;
-rw-r--r-- 1 mcdx staff 124169136 9 14 19:10 ./Library/Caches/com...
-rw-r--r-- 1 mcdx staff 164184036 9 14 19:10 ./Library/Caches/com...
-rw-r--r-- 1 mcdx staff 214697712 9 18 10:19 ./Library/Caches/com...
locate實現快速查找此命令在一個存有系統中全部文件名和目錄名的數據庫中去查找
此數據庫不會實時更新，可以手動更新：sudo updatedb
-i 參數忽略大小寫
它是按字符串進行查詢，查詢的結果是完整的文件路徑：
mcdx@ubuntu:~$ locate readme.md
/home/mcdx/git/xiangmuxiezuo/dazuoye/36_熱門職位標簽/seiya/readme.md
mcdx@ubuntu:~$ locate -i readme.md
/home/mcdx/Downloads/redis-stable/README.md
/home/mcdx/Downloads/redis-stable/deps/README.md
/home/mcdx/git/xiangmuxiezuo/README.md
/home/mcdx/git/xiangmuxiezuo/dazuoye/36_熱門職位標簽/seiya/readme.md
mcdx@ubuntu:~$ locate /usr/bin/python3
/usr/bin/python3
/usr/bin/python3-config
/usr/bin/python3.5
/usr/bin/python3.5-config
/usr/bin/python3.5m
/usr/bin/python3.5m-config
/usr/bin/python3m
/usr/bin/python3m-config
mcdx@ubuntu:~$ locate ~/a
/home/mcdx/a.py
-l 限制打印查詢結果的數量：
mcdx@ubuntu:~$ locate -l 2 README.md
/home/mcdx/Downloads/redis-stable/README.md
/home/mcdx/Downloads/redis-stable/deps/README.md
-c 打印查詢數量
mcdx@ubuntu:~$ locate -c app.py
47
如果查詢結果中有目錄，自然也會打印目錄以及目錄中的全部子目錄以及文件
這就是所謂全庫搜索按字符串查詢，沒有目錄的概念，十分強硬：
mcdx@ubuntu:~/test/shiyan/shiyan$ locate /home/mcdx/test/shiyan/shiyan/i
/home/mcdx/test/shiyan/shiyan/image
/home/mcdx/test/shiyan/shiyan/items.py
/home/mcdx/test/shiyan/shiyan/image/full
/home/mcdx/test/shiyan/shiyan/image/full/1cea...7452aca3e756a44e.jpg
/home/mcdx/test/shiyan/shiyan/image/full/1f1a...9b62f08a50145016.jpg
/home/mcdx/test/shiyan/shiyan/image/full/223d...f662e849e08fd855.jpg
/home/mcdx/test/shiyan/shiyan/image/full/26dd...9a1a6215da800f8.jpg
/home/mcdx/test/shiyan/shiyan/image/full/2c50...225726fbce3aba31.jpg
whereis跟前面的 locate 類似也是在那個存儲字符串的庫里查找字符串
不過它只查找二進制文件（也就是可執行文件）、源、man 手冊
這段待補充，先寫個例子：
mcdx@ubuntu:~$ whereis flask
flask: /usr/local/bin/flask
mcdx@ubuntu:~$ whereis pip3
pip3: /usr/bin/pip3 /usr/local/bin/pip3.5 /usr/share/man/man1/pip3.1.gz
which用于在 PATH 環境變量中查找 shell 命令的完整路徑shell 命令其實也是一個可執行文件的文件名
此命令默認打印第一個符合的結果：
-a 參數打印全部結果
mcdx@ubuntu:~$ which tree
/usr/bin/tree
mcdx@ubuntu:~$ which python
/usr/bin/python
