b block (buffered) special
c character (unbuffered) special
d directory
p named pipe (FIFO)
f regular file
l symbolic link; this is never true if the -L option or the -follow option is in effect, unless the symbolic link is broken. If you want to search for
symbolic links when -L is in effect, use -xtype.
s socket
D door (Solaris)
1
2
3
4
5
6
7
8
9
2） sed -e ‘s/.*.//’
任意字符到. 替换为 空，即取得后缀名
3） sort
排序
4） uniq -c
-c, –count
prefix lines by the number of occurrences
第一列统计对应的行数
5) sort -n
compare according to string numerical value
以数字列排序
排序结果为：
1 docx
2 jar
2 part
4 xlsx
5 rar
6 PDF
17 xls
122 doc
149 zip
322 json
21305 pdf
154981 jpg
1559454 txt
3029912 html
