# iptableの設定を確認する
$ sudo iptables -nL

# カレントディレクトリ中のサブディレクトリとその中にあるファイルを表示する
$ ls .??*

# ディスク使用量の多いディレクトリのTOP10を降順に表示する
$ sudo du -S | sort -rn | head -n 10

# プロセスが使用しているcpuでソートして表示する
ps aux --sort=-%cpu | grep -m 11 -v `whoami`


# モジュールをアップデートする
yes '' | sudo perl -MCPAN -e "CPAN::Shell->install(CPAN::Shell->r)"

# モジュールのバージョン番号とパスを確認する
perl -le 'eval "require $ARGV[0]";print ${"${ARGV[0]}::VERSION"};print qx/perldoc -ml $ARGV[0]/' MODULE_NAME

# run debugger "stand-alone"
perl -d -e 42

# run program, but with warnings
perl -w my_file

# run program under debugger
perl -d my_file

# just check syntax, with warnings
perl -wc my_file

# useful at end of "find foo -print"
perl -nle unlink

# simplest one-liner program
perl -e 'print "hello world!\n"'

# add first and penultimate columns
perl -lane 'print $F[0]  $F[-2]'

# just lines 15 to 17
perl -ne 'print if 15 .. 17' *.pod

# in-place edit of *.c files changing all foo to bar
perl -p -i.bak -e 's/\bfoo\b/bar/g' *.c

# command-line that prints the first 50 lines (cheaply) 
perl -pe 'exit if $. > 50' f1 f2 f3 ...

# delete first 10 lines
perl -i.old -ne 'print unless 1 .. 10' foo.txt

# change all the isolated oldvar occurrences to newvar
perl -i.old -pe 's{\boldvar\b}{newvar}g' *.[chy]

# command-line that reverses the whole file by lines
perl -e 'print reverse <>' file1 file2 file3 ....

# find palindromes
perl -lne 'print if $_ eq reverse' /usr/dict/words

# command-line that reverse all the bytes in a file
perl -0777e 'print scalar reverse <>' f1 f2 f3 ...

# command-line that reverses the whole file by paragraphs
perl -00 -e 'print reverse <>' file1 file2 file3 ....

# increment all numbers found in these files
perl i.tiny -pe 's/(\d)/ 1  $1 /ge' file1 file2 ....

# command-line that shows each line with its characters backwards
perl -nle 'print scalar reverse $_' file1 file2 file3 ....

# delete all but lines between START and END
perl -i.old -ne 'print unless /^START$/ .. /^END$/' foo.txt

# binary edit (careful!)
perl -i.bak -pe 's/Mozilla/Slopoke/g' /usr/local/bin/netscape

# look for dup words
perl -0777 -ne 'print "$.: doubled $_\n" while /\b(\w)\b\s\b\1\b/gi'

# command-line that prints the last 50 lines (expensively)
perl -e '@lines = <>; print @lines[ $#lines .. $#lines-50' f1 f2 f3 ...