Problem Solver
Everything is similar to the previous two videos in the series. The only difference is in this video we will learn how to use chmod with octal numbers.
In Octal
This tutorial covers how to use the chmod command to change the access permission of files and directories.
In Linux, the file is associated with an owner and a group and assigned with permission access rights for three different classes of users:
File permissions can be changed. In order to do that we make use of chmod command.
There are three file permissions that apply to each class:
-rw-r--r-- 12 yash staff 128 Oct 2 12:31 myfile.txt |[-][-][-]- [------] [---] | | | | | | | | | | | | | +-----------> 7. Group | | | | | +-------------------> 6. Owner | | | | +--------------------------> 5. Alternate Access Method | | | +----------------------------> 4. Others Permissions | | +-------------------------------> 3. Group Permissions | +----------------------------------> 2. Owner Permissions +------------------------------------> 1. File Type
Everything is similar to the previous video the only difference is we will see the behavior of directories and its contents when changing their permissions.
This tutorial covers how to use the chmod command to change the access permission of files and directories.
In Linux, the file is associated with an owner and a group and assigned with permission access rights for three different classes of users:
File permissions can be changed. In order to do that we make use of chmod command.
There are three file permissions that apply to each class:
-rw-r--r-- 12 yash staff 128 Oct 2 12:31 myfile.txt |[-][-][-]- [------] [---] | | | | | | | | | | | | | +-----------> 7. Group | | | | | +-------------------> 6. Owner | | | | +--------------------------> 5. Alternate Access Method | | | +----------------------------> 4. Others Permissions | | +-------------------------------> 3. Group Permissions | +----------------------------------> 2. Owner Permissions +------------------------------------> 1. File Type
This tutorial covers how to use the chmod command to change the access permission of files and directories.
In Linux, the file is associated with an owner and a group and assigned with permission access rights for three different classes of users:
File permissions can be changed. In order to do that we make use of chmod command.
There are three file permissions that apply to each class:
-rw-r--r-- 12 yash staff 128 Oct 2 12:31 myfile.txt |[-][-][-]- [------] [---] | | | | | | | | | | | | | +-----------> 7. Group | | | | | +-------------------> 6. Owner | | | | +--------------------------> 5. Alternate Access Method | | | +----------------------------> 4. Others Permissions | | +-------------------------------> 3. Group Permissions | +----------------------------------> 2. Owner Permissions +------------------------------------> 1. File Type
ANSI Escape Code
https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
In this video, we will learn how to use the echo command. The arguments passed to echo are printed to the standard output.
Echo is commonly used in shell scripts to display a message or output the results of other commands.
Although it is not necessary to enclose arguments in double-quotes it is good practice to do so.
If using ” each character enclosed within is preserved. Variable and commands will not be expanded.
Echo can be used with pattern matching characters, such as the wildcard characters.
echo "My txt files are: *txt"
Creating a variable in the shell for the current session. Don’t leave any space between equal sign.
myString="Hello World" x=10
Display variable:
echo $myString echo "x"
Echo can redirect commands output.
echo "Directory contents: $(ls -l)"
| Command | Effect |
|---|---|
| ^O | Save changes |
| ^X | Exit nano |
When working on the command line, quite often you will need to create or edit files. Two of the most famous and powerful command-line editors are Vim and emacs. On the other hand, they are equally difficult to learn. But there is a simpler editor available to just get things done and that is nano.
All commands are prefixed with a control(^) character or metacharacter(M). caret symbol represents control and M represents Meta. Control will generally be your control key. Meta character depends on the keyboard setup. It can either be an Esc key, alt key, or a special meta key.
In this video, I will help you learn the basic usage of the nano editor, including how to create an open file, edit a file, save a file, search and replace text, cut and paste text, and more.
| Command | Effect |
|---|---|
| ^F | Forward one character |
| ^B | Back one character |
| ^Space | Forward one word |
| M-Space | Back one word |
| ^P | Previous line |
| ^N | Next line |
| ^A | Beginning of the current line |
| ^E | End of the current line |
| M-( | Beginning of the current paragraph |
| M-) | End of the current paragraph |
| M-\ | The first line of the file |
| M-/ | The last line of the file |
| ^_ | Move the cursor to a specific line |
| Command | Effect |
|---|---|
| ^W | Search pattern |
| M-W | Move to the next match |
| ^\ | Search pattern and replace |
| Command | Effect |
|---|---|
| M-A | Select text(set a selection mark) |
| ^6 | Cancel the selection press |
| M-6 | Copy the selected text to the clipboard |
| ^K | Cut the selected text |
| ^U | Paste the text at the cursor position |
| Command | Effect |
|---|---|
| ^O | Save changes |
| ^X | Exit nano |
In this video, we will learn how to use less command. less is a command-line utility that displays the content of a file or a command output, one page at a time. The less command is mostly used for opening large files.
The general syntax for using less command is:
less [options] filename
It is also possible to use less with other commands output.
ls /etc | less
When opening a file that is too large to fit in one page, you will see the colon at the bottom of the screen. What makes less more appealing is its ease of file navigation.
| Command | Output |
|---|---|
| f or space bar | next page |
| j, down key or enter | next line |
| k or up key | previous line |
| b | previous page |
| G | end of the file |
| g | start of the file |
| [n]G | goes to nth line |
| /[pattern] | top-down search |
| ?[pattern] | bottom-up search |
| n | next search result |
| N | previous search result |
| Option | Effect |
|---|---|
| -N | show line numbers |
| -X | preserve screen content after exiting less |
| +F | watch out for changes being made to the file |
Thank you 🙂
In this video, we will learn how to use touch command. The main purpose of this command is to change file access and modification time but it can be used to create a new file. In simple terms, it is used to change the timestamp of a given file.
touch can create a new file too. I find it much simpler to create a new file using touch. It is possible to create a file with any file extension. Moreover, you can create multiple files with just one command.
Remember you can always type man touch to learn more about the command.
We will also learn about some flags along with touch command:
-t = pass in custom timestamp
-a = just change access timestamp
-m = just change the modified timestamp
-r = copy timestamp from another file
Thank You!
In this video we will learn how to use stat command. stat is a command-line utility that displays detailed information about given files or file system. In simple words stat is used to display file information or properties.
Remeber you can always type man stat to learn more about the command.
We will also learn about some flags along with stat command:
-f = this flag is used for formatting custom output
Thank you 🙂
In this video we will learn how to use alias and unalias command. alias are like custom shortcuts used to represent a command executed with or without custom options. You can save yourself some time by creating aliases for your most used commands.
Whereas unalias is used to remove the shortcut which was initially created. Pretty simle!
Thank you 🙂