シェル芸メモ

shell_tricks.md

忘れないように。というか、忘れてもいいように

• extract Nth line

# extract 5th line from <file>
sed '5!d' $file

• count num of specific words per lines

grep -n -o 'specific word' $file | uniq -c

# grep -n : print line number with output lines
# grep -o : show only the part of a line matching PATTERN

• 実行例

  $ grep -w -n -o 'message' rfc2660.txt | uniq -c | sort -nr | head -10
        2 778:message
        2 760:message
        2 581:message
        2 480:message
        2 238:message
        1 828:message
        1 825:message
        1 801:message
        1 800:message
        1 799:message

• date format

date '+%Y/%m/%d %H:%M:%S'