#+TITLE: bash commands
#+DATE: 2021-08-30
#+STARTUP: indent
#+OPTIONS: num:nil

* DONE work in bash tutorial
  :LOGBOOK:
  CLOCK: [2021-09-08 mié 18:52]--[2021-09-08 mié 19:22] =>  0:30
  CLOCK: [2021-09-04 sáb 16:04]--[2021-09-04 sáb 16:34] =>  0:30
  CLOCK: [2021-09-04 sáb 15:19]--[2021-09-04 sáb 15:49] =>  0:30
  :END:



* Execute stuffs


* Show command history

: history

The file can be found in the user home:

: /home/user/.bash_history




** Backup a file

  Using "cp"

  : cp bbdb{,.bak}

  : bbdb.bak

  Backups with tar (tape archiver)

  Back up of "home"

  * c = create file
  * v = verbose
  * f = write to a file/device
  * z = compress the file (gzip) "tar.bz"
  * j = compress the file (bzip2)

  : tar -czvf /tmp/home.tar.gz /home

** Simple code to encrypt

   Encrypt:

   : gpg -c X
   : gpg X

   Use the code to remove the original file:

   : shred --remove X


** Download files

This code download the file and the argument ~-O~ is to rename the file

#+begin_example
wget https://filetodownload.org -O new_file
#+end_example

* Devices

- mount /what /where
  - what = device name
  - where = directory
    - /mnt = devices that mount occasionally
    - /media = devices that mount frequently

: run/$USER/media/$LABEL


* Evaluate time to load

In emacs:

: time emacs --eval '(save-buffers-kill-terminal)'

* Cool commands

: cal # calendar
: clear # clear output
: uname # display system information (-r, -p, -a)
: wc # wordcount (file name)
: date # check the date


* References:

 * [[https://wiki-dev.bash-hackers.org/][The bash hackers wiki]]
 * [[https://link.springer.com/content/pdf/bfm%3A978-1-4302-6829-1%2F1.pdf?error=cookies_not_supported&code=2e41714e-ca8f-4796-a077-3243c836ec90][Beginning the linux command line]]
 * [[https://pandoc.org/][Pandoc manual]]
 * [[https://stackoverflow.com/][stackoverflow]]