#+title: Bash
#+setupfile: ../org-templates/page.org

** Split large text file into smaller files with equal number of lines
#+begin_src shell
split -l 60 bigfile.txt prefix-
#+end_src

** Loop through lines of file
#+begin_src shell
while read line; do
    echo "$line";
done </path/to/file.txt
#+end_src

** Use grep to find URLs from HTML file

#+begin_src shell
cat urls.html | grep -Eo "(http|https)://[a-zA-Z0-9./?=_%:-]*"
#+end_src

- ~grep -E~: egrep
- ~grep -o~: only output what has been grepped
- ~(http|https)~: either http OR https
- ~a-zA-Z0-9~: match all lowercase, uppercase, and digits
- ~.~: match period
- ~/~: match slash
- ~?~: match ?
- ~=~: match =
- ~_~: match underscore
- ~%~: match percent
- ~:~: match colon
- ~-~: match dash
- ~*~: repeat the [...] group any number of times