VIM indentation

On Fedora 25
go to /etc
edit file vimrc
add

set tabstop=4
set shiftwidth=4

save and close

Laptop Can See Wireless Networks But One

    If your laptop can't connect some Wi-Fi networks you should try to decrease the Channel value on router.
Some wireless adapters are not able to connect channel 12-13-14 so you should try 11 or lower.

Note to myself

apt-get -f upgrade
apt-get update
dpkg -i bla bla bla

http://www.thegeekstuff.com/2009/04/vi-vim-editor-search-and-replace-examples/

http://www.tecmint.com/wc-command-examples/

http://www.thegeekstuff.com/2012/10/15-linux-split-and-join-command-examples-to-manage-large-files/

http://www.livefirelabs.com/unix_commands/5-unix-diff-command-examples-of-how-to-compare-two-text-files.htm

http://www.joshstaiger.org/archives/2005/07/bash_profile_vs.html

https://www.cyberciti.biz/tips/howto-keep-file-safe-from-overwriting.html

Creating group, giving sudo privileges and adding user to the group

Step 1: Login to root account
..$ su

Step 2: Adding user
..# useradd -m frank

Step 3: Creating group
..# groupadd rangers

Step 4: Edit sudoers and add rangers into
..# vim /etc/sudoers

# Allow members of group sudo to execute any command
%sudo   ALL=(ALL:ALL) ALL
%rangers  ALL=(ALL:ALL) ALL

save and exit

Step 5: Adding frank to rangers

..# usermod -a -G rangers frank

Finished.

Now you have a user frank in the rangers group, which was added to sudoers file.

You should able to use sudo while you are frank.

locate command

Before using locate  command, you should update db
..$ sudo updatedb

then you can use locate.
..$ locate mypicture

Fast Search

There are couple of ways to make searching.

One of them:

ls | grep

..$ ls | grep dir
workingdir
direct
dire

It shows us anything contains dir.



note:
cat /etc/issue

shows you to which os currently you have.

Internal and External Commands

Internal commands are buil-in commands.
If you don't know the type of a command, you can use "type" command:


..$ type cd
cd is a shell builtin

..$ type pwd
pwd is a shell builtin

..$ type bash
bash is /bin/bash

There is a trick about "type" command:

..$ type -a pwd
pwd is a shell builtin
pwd is /bin/pwd

"-a" option shows us is the command duplicated by external command or not.
let's understand it with "time" command:

..$ time pwd
/home/user

real 0m0.000s
user 0m0.000s
sys 0m0.000s

..$/usr/bin/time pwd
/home/user
0.00user 0.00system 0:00.04elapsed 0%CPU
(0avgtext+0avgdata 2240maxresident)k
64inputs+0outputs (1major+83minor)pagefaults 0swaps

So what happened up there:
When we typed "time pwd" we used the internal(built-in) time command
Then we typed "/usr/bin/time pwd"    that was the external time command
I hope this is a helpful explanation about difference between internal and external commands.