linux commands

mkfifo
    > mkfifo my_pipe
    > cat a.txt > my_pipe
    > cat my_pipe

ldd
    > ldd /usr/java/jre1.5.0_11/bin/java

xmlwf
    > curl -s 'http://bashcurescancer.com' > bcc.html
    > xmlwf bcc.html

删除文件的恢复

lsof
    > cp ~/code/demo.cpp /tmp/workspace/test.cpp
    > cd /tmp/workspace
    > less test.cpp
    > rm -f test.cpp
    > lsof | grep test.cpp
    less      6173  dirkxu    4r      REG      253,0     2876     669315 /tmp/workspace/test.cpp (deleted)
    > cat /proc/6173/fd/4 > recover.cpp
    > cmp ~/code/demo.cpp recover.cpp

文件的分割、合并、校验

split [OPTION] [INPUT [PREFIX]]
       -b, --bytes=SIZE
              put SIZE bytes per output file

       -C, --line-bytes=SIZE
              put at most SIZE bytes of lines per output file

       -d, --numeric-suffixes
              use numeric suffixes instead of alphabetic

       -l, --lines=NUMBER
              put NUMBER lines per output file
    > split -b 3k larger.txt small
    > ls -lh /etc | split -l 40 - small_line

    #combine multi files into one file
    > cat smalla smallb smallc > new_larger
    > cat small_linea small_lineb >> history

    #validate whether the new file equals the old file
    > md5sum larger new_larger