The Bash Environment

The Bash Environment

• Environment Variables

  We can view the contents of a given environment variable with the echo command followed by the “$” character and an environment variable name. For example, let’s take a look at the contents of the PATH environment variable:

  kali@kali:~$ echo $USER
  kali
  kali@kali:~$ echo $PWD
  /home/kali
  kali@kali:~$ echo $HOME
  /home/kali
  kali@kali:~$ echo $PATH
  /usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin

  An environment variable can be defined with the export command. For example, if we are scanning a target and don’t want to type in the system’s IP address repeatedly, we can quickly assign it an environment variable and use that instead:

The Environment Variable , In Case Search From Command In The Machine , Search The Path’s In Environment Variable General In Linux Machine IF U Want Show Path’s And Other Information's Enter Command env

U Can Edit Value In Variables , Set Value Of Variable In Case Login The Machine

Name="OSCP"
echo $Name # OSCP

But In Case Open New Session In The Same Terminal , Not Show This Variable

In Case U Need Complete The Same Variable in All Sessions , Using export

In Case U Need Remove Value From Any Variable Using unset Command

---

General In Case Search From Command In Variable Env , Search in 1st Path , IF Not Found , Search 2nd Path IF Not Found Search 3rd And , ETC … In Case Use Bad sudo

---

Bash History

In Linux Store All Command Used In history File In Case Use Specific Command Using ID In History Use !

In Case Type The ID Command From History And Type Enter , Show The Command , If U Need Update In Case Type The ID Command And Type Space , Convert To The Command If U Need Edit

---

In Case Type !! Use The Last Command In History File, Or Use The Last ID Command

---

In Case Type Ctrl+r Open Search In Command In Terminal After Used

---

U Can Separate 1st Command And 2nd Command Using Semicolon ; It doesn't matter if the first thing ended properly or not

ls ; ls

Execute a specific command, and if it succeeds, another specific command is executed. In the event of failure, the execution will not be completed Using &&

cdc && ls # Not Execute ls Command 
cd .. && ls # In Case Not Return Error Execute ls Command