Commit 2f3ede1e authored by Jyothis Jagan's avatar Jyothis Jagan
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Update session1.md

parent 3cf34e5e
......@@ -4,14 +4,14 @@ Refer [UNIX / Linux : What Is a Shell? What are different Shells?](https://www.t
> A shell is a program that provides an interface between a user and an operating system (OS) kernel. An OS starts a shell for each user when the user logs in or opens a terminal or console window.
>
> A kernel is a program that:
>
> * Controls all computer operations.
> * Coordinates all executing utilities
> * Ensures that executing utilities do not interfere with each other or consume all system resources.
> * Schedules and manages all system processes.
>
> By interfacing with a kernel, a shell provides a way for a user to execute utilities and programs.
......@@ -26,17 +26,17 @@ Refer [UNIX / Linux : What Is a Shell? What are different Shells?](https://www.t
Refer [How to Manage Files from the Linux Terminal: 11 Commands You Need to Know](https://www.howtogeek.com/107808/how-to-manage-files-from-the-linux-terminal-11-commands-you-need-to-know/ "How to Manage Files from the Linux Terminal: 11 Commands You Need to Know")
1. ls – List Files
2. cd – Change Directory
3. rm – Remove Files
4. rmdir – Remove Directories
5. mv – Move Files
6. cp – Copy Files
7. mkdir – Make Directories
8. ln – Create Links
9. chmod – Change Permissions
10. touch – Create Empty Files
11. mc – A Full File Manager (TUI - Terminal User Interface)
1. `ls` – List Files
2. `cd` – Change Directory
3. `rm` – Remove Files
4. `rmdir` – Remove Directories
5. `mv` – Move Files
6. `cp` – Copy Files
7. `mkdir` – Make Directories
8. `ln` – Create Links
9. `chmod` – Change Permissions
10. `touch` – Create Empty Files
11. `mc` – A Full File Manager (TUI - Terminal User Interface)
# Filesystem Hierarchy Standard
......@@ -52,9 +52,9 @@ Refer [Filesystem Hierarchy Standard](https://refspecs.linuxfoundation.org/FHS_3
* Device files
## /etc
* Host-specific system configuration like hostname, ip address, dns server address, list of users and groups etc.
* /etc/hosts can be used as a simple local DNS system.
* /etc/resolv.conf specifies the nameservers for resolver lookups.
* everything in /etc/skel gets copied to home directory of newly created user
* `/etc/hosts` can be used as a simple local DNS system.
* `/etc/resolv.conf` specifies the nameservers for resolver lookups.
* everything in `/etc/skel` gets copied to home directory of newly created user
## /home
* User home directories
## /lib
......@@ -81,15 +81,15 @@ Refer [Filesystem Hierarchy Standard](https://refspecs.linuxfoundation.org/FHS_3
## /tmp
* Temporary files
## /usr
* only package manager is supposed to write to /usr.
* only package manager is supposed to write to `/usr`.
### /usr/local
* It is for system administrators, for example if we create some custom scripts, we can add it in /usr/local/bin.
* It is for system administrators, for example if we create some custom scripts, we can add it in `/usr/local/bin`.
## /var
* Any file that keeps growing during the system operation goes to /var. examples includes log files, database files, debs downloaded by apt etc.
* Any running program should only write important data (that should be persisted during reboots) to /var or to /home.
* Any file that keeps growing during the system operation goes to `/var`. examples includes log files, database files, debs downloaded by apt etc.
* Any running program should only write important data (that should be persisted during reboots) to `/var` or to `/home`.
### /var/cache
* Usually used for data that could be removed without much issues (things that could be downloaded again)
* /var/cache/apt/archives contains .deb files downloaded by apt.
* `/var/cache/apt/archives` contains `.deb` files downloaded by apt.
### /var/lib
* Contains important data, usually database programs keep their data there.
......@@ -97,18 +97,18 @@ Refer [Filesystem Hierarchy Standard](https://refspecs.linuxfoundation.org/FHS_3
Refer [Bash Environment Variables Tutorial](https://linuxhint.com/bash-environment-variables/ "Bash Environment Variables Tutorial")
* $HOME - the path to the home directory of the user.
* $PATH - directories in which the shell looks for commands.
* $PS1 - first prompt string.
* `$HOME` - the path to the home directory of the user.
* `$PATH` - directories in which the shell looks for commands.
* `$PS1` - first prompt string.
# Miscellaneous
## Hidden Files
* Starts with dot(.)
* Usually used for user specific configurations.
* .bashrc is used for configuring bash. .bashrc file can be found in home directory for each user.
* `.bashrc` is used for configuring bash. `.bashrc` file can be found in home directory for each user.
* Use `ls -a` in your home directory, you will see all of them
* ~/.ssh is a hidden directory.
* `~/.ssh` is a hidden directory.
# Tasks To Do
When : Whenever you feel confident of trying!
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