리눅스 프로세스 명령어(linux process command) 2. filtering

1. I/O redirection

1-1 > and >>

• >: overwrite

command > filename

• >>: append

command >> filename

* 0: stdin, 1: stdout, 2: stderr

* if make to dispose output, redirect to /dev/null

• <: using the contents of file, run command.

command < filename

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2. pipeline

command1 | command2

command1 output goes into command2 input(filename)

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3. sort

sort filename

option	example	explain
-k	sort -k 1,2 data.txt	sorting contents in data.txt following key 1. if key 1 value same, follow key 2
-n	sort -n data.txt	sorting contents in data.txt by its numeric value
-r	sort -r data.txt	sorting contents in data.txt in reverse

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4. find

find start_dir search_option command

• search_option

option	example	explain
-name	find -name *.out command	find file named *.out
-size	find -size 0 command	find 0 byte size file

• command

option	example	explain
-exec	find -name *.out -exec rm -i {} ';'	find file named *.out and execute rm -i searched_file
-print	find -size 0 -print	find 0 byte size file and print

   * -exec using found file, {}

   * -exec must end with char ; (escape sequence \;, single char ';')