linux : 라인수 세기

라인 수가 궁금할 때는 wc 를 사용하면 된다.

$ wc --help
Usage: wc [OPTION]... [FILE]...
  or:  wc [OPTION]... --files0-from=F
Print newline, word, and byte counts for each FILE, and a total line if
more than one FILE is specified.  A word is a non-zero-length sequence of
characters delimited by white space.

With no FILE, or when FILE is -, read standard input.

The options below may be used to select which counts are printed, always in
the following order: newline, word, character, byte, maximum line length.
  -c, --bytes            print the byte counts
  -m, --chars            print the character counts
  -l, --lines            print the newline counts
      --files0-from=F    read input from the files specified by
                           NUL-terminated names in file F;
                           If F is - then read names from standard input
  -L, --max-line-length  print the maximum display width
  -w, --words            print the word counts
      --help     display this help and exit
      --version  output version information and exit

GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>
Full documentation <https://www.gnu.org/software/coreutils/wc>
or available locally via: info '(coreutils) wc invocation'

$ wc -l test.txt
1 test.txt

위와 같이 -l, --lines 옵션을 사용하면 된다. 

$ cat test.txt
ab cd
aa
$ wc -l test.txt
1 test.txt

주의할 점은 줄바뀜을 센다는 거다.

$ grep -Hc ".*" test.txt
test.txt:2

grep -Hc 옵션을 사용하는게 원하는 결과에 가깝다. 😕

참고 : https://www.thegeekdiary.com/how-to-count-lines-in-a-file-in-unix-linux/

How to Count lines in a file in UNIX/Linux – The Geek Diary