working with commandline

commanline

---     bash
enter the command 
cat /etc/passwd

and you will see the list of all the user names and bash assigned to the user 
Ex.kia:x:2000:2000:kia,,,:/home/kia:/bin/bash

each bash has it's configuration as well as global configuration

global configuration file is stored in

/etc/profile    --     profile is the file which stores global configuration for bash


user home directory contains lots of hidden files all the hidden files starts with . ex. .bashrc
.bashrc file contanis alias with is get called when bash starts

linux only looks for the executable files in the path only now in current directory

here 
la -a

.     --  single dot means current directory
..    --  parent directory

to make linux to find the executable you need to add path to the path environment variable

type env  in command line and you wil see whole list of environment variable

you can see the path there 


you can add the path in path env by

PATH = $PATH:[your new path to add]

and now linux will find the files you wnat in your path

you can create variable with

VARIABLE=VALUE;

AND export thsi variable to env by useing 
export VARIABLE

and echo the variable with

echo $VARIABLE



uname command with return what operating system you are using
uname -a will give all the information about your currently running system


man is used to get help  (manuel)


man history         will give you manual page for history command
man -k [file]       will search all the man pages for that specific [file] string

exec command executes the command and exit the shell

if you use the exec ls command then teminal will show the ls and will exit because of exec command that is why most of the time this command is used to end the bash file