sed with re sed -r '' file # -r, --regexp-extended match newline with grep grep '^$' file.txt split file to files split -l [number] --numeric-suffixes=[from number] --additional-suffix=[suffix] file [prefix] -l, --lines=NUMBER -d, --numeric-suffixes[=from number] python - Ascii chr(97) # 'a' ord('a') # 97 shell print '' until Ctrl-C yes '' yes {1..9} | head -n 3 generate '1\n2\n3\n...n\n' echo {n1..n2} | sed -r 's/ /\n/g' cut -- usage cut -d ' ' -f n1-n2 -d follows a single char -f follows points of splited field search apps, lib or etc pacsearch pacsearch - Add color and install information to a pacman -Ss search Usage: pacsearch <pattern> Example: pacsearch ^gnome dictionary with curl curl dict://dict.org/d:computer history of reviewed files less ~/.local/share/recently-used.xbel split large file, then merge split -b 100m file_name cat file_name* > file_name DNS for fxcking GFW 116.255.162.155 60.190.217.130 sniffer http or tcp sudo tcpdump -i wlan0 -s 0 -l -w out