Command Flags

Lesson Requirements

Complete Using Ubuntu

Intro to Flags

When you give the computer a command, you can also give it special flags to tell it how to do the task. These flags are special options that change how the command works.

For example, if you want to copy a file from one place to another, you would tell the computer to use the `cp1 command. But if you want to copy the file and keep a backup of the original file, you would use the “-b” flag to tell the computer to make a backup.

Flags can do many things, like changing the way the command works, giving you more information, or making the command safer to use. However, you need to know which flags to use for each command, just like you need to know which buttons to press in a game to make your character do something special.

help Flag

Most Linux commands have a help option that provides information about the command and how to use it. To access the help for a command, simply type the command name followed by “—help” or “-h” and press Enter.

For example, to get help for the ls command (which is used to list the contents of a directory), you can type ls --help or ls -h in the command line and press “Enter”. This will display a message that explains how to use the command, what flags or options are available, and what they do.

The help message may include examples of how to use the command, as well as explanations of any technical terms or concepts that might be confusing. This way, even if you’ve never used the command before, you can learn how to use it quickly and easily.

The “help” feature is like having a teacher or tutor available whenever you need help with a command. It can help you become more familiar with the Linux operating system and improve your skills as a computer user.

Flags for “touch” command

The touch command in Linux is used to create a new empty file. Similar creating a new sheet of paper to write on. You can use some flags with the “touch” command to make it do different things. Here are some of the most common ones:

“-a”: This flag updates the “access time” of a file. Similar checking the last time you opened a book. Here’s an example:
```
touch -a myfile.txt
```
“-m”: This flag updates the “modification time” of a file. Similar checking the last time you wrote something on a sheet of paper. Here’s an example:
```
touch -m myfile.txt
```

Activity: Update Access Time of a File

Create a new file called “mydiary.txt” using the touch command and update its access time using the -a flag.

Activity: Update modification time of a file

Create a new file called “grocerylist.txt” using the touch command and update its modification time using the -m flag.

Flags for “rm” command

The “rm” command in Linux is used to remove or delete files or directories. Similar throwing away a piece of paper or a folder. You can use some flags with the “rm” command to make it do different things. Here are some of the most common ones:

“-r”: This flag stands for “recursive”. It’s used to remove a directory and all of its contents. Similar throwing away an entire folder and everything inside it. Here’s an example:
```
rm -r myfolder/
```
“-f”: This flag stands for “force”. It’s used to remove files or directories without prompting you for confirmation. Similar throwing something away without asking your parents for permission first. Here’s an example:
```
rm -f myfile.txt
```
“-i”: This flag stands for “interactive”. It’s used to prompt you for confirmation before removing a file or directory. Similar asking you if you’re sure you want to throw something away before you do it. Here’s an example:
```
rm -i myfile.txt
```
“-v”: This flag stands for “verbose”. It’s used to show you more information about what’s happening as files or directories are being removed. Similar telling you step by step what’s happening as you throw something away. Here’s an example:
```
rm -v myfile.txt
```

Activity: Removing All Contents in Directory

Create a directory called “myfolder”. Then, use the rm command with the -r flag to remove a directory called “myfolder” and all of its contents.

Activity: Remove without Confirmation

Create a file called “myphoto.jpg”. Then, use the rm command with the -f flag to remove a file called “myphoto.jpg” without prompting you for confirmation.

Activity: Remove All Contents with Confirmation

Create a directory called “mydocuments”. Then, use the rm command with the -i flag to prompt you for confirmation before removing a directory called “mydocuments” and all of its contents.

Activity: Remove Contents with Informatino

Use the rm command with the -v flag to show you more information about what’s happening as you remove a file called “mypaper.docx”.

Flags for “ls”

The ls command in Linux is used to list the contents of a directory. You can use some flags with the “ls” command to make it do different things. Here are some of the most common ones:

“-l”: This flag stands for “long”. It’s used to display a detailed listing of the files in the directory. It shows you information like the file permissions, owner, size, and date modified. Here’s an example:
```
ls -l myfolder/
```
“-a”: This flag stands for “all”. It’s used to show all files, including hidden files, in the directory. Hidden files are files that start with a dot, like .git or .bashrc. Here’s an example:
```
ls -a myfolder/
```
“-h”: This flag stands for “human-readable”. It’s used to display file sizes in a more readable format, like “10K” instead of “10240”. Here’s an example:
```
ls -lh myfolder/
```
“-t”: This flag stands for “time”. It’s used to sort files by the time they were last modified, with the most recent files first. Here’s an example:
```
ls -lt myfolder/
```

Activity:

Use the ls command with the -l flag to display a detailed listing of the files in a directory called “myfolder”.

Activity:

Use the ls command with the -a flag to show all files, including hidden files, in a directory called “mydocuments”.

Activity:

Use the ls command with the -h flag to display file sizes in a more readable format in a directory called “mypictures”.

Activity:

Use the ls command with the -t flag to sort files in a directory called “myvideos” by the time they were last modified, with the most recent files first.

Activity:

Use the ls command with both the -l and -a flags to display a detailed listing of all files, including hidden files, in a directory called “myfiles”.

Activity:

Use the ls command with both the -h and -t flags to display file sizes in a more readable format and sort files in a directory called “mydownloads” by the time they were last modified, with the most recent files first.

Flags for “mkdir” command

The mkdir” command is used in Linux to create new directories or folders on the computer. Here are some common flags for the mkdir command:

“-p”: The “-p” flag stands for “parents” and is used to create a directory with any missing parent directories. For example, if you want to create a folder called “documents” inside a folder called “user” but the “user” folder doesn’t exist yet, you can use the command to create both folders at once.:

mkdir -p user/documents
-m : The “-m” flag stands for “mode” and is used to set the permissions for the new directory. Permissions determine who can access and modify the files and folders in a directory. For example, if you want to create a new directory called “public” with read and write access for everyone, you can use the command:

mkdir -m 777 public
“-v” : The “-v” flag stands for “verbose” and is used to display a message when the directory is successfully created. For example, if you want to create a new directory called “photos” and display a message when it is created, you can use the command:

mkdir -v photos

“rmdir” Flags

The rmdir command in Linux is used to remove or delete directories. Here are some common flags for the rmdir command, explained in a way that middle school students can understand:

-p: The “-p” flag stands for “parents” and is used to remove a directory along with its parent directories if they are empty. For example, if you want to delete a folder called “pictures” and its parent folder called “vacation” if both folders are empty, you can use the command:

rmdir -p vacation/pictures.
“-v” : The “-v” flag stands for “verbose” and is used to display a message when the directory is successfully removed. For example, if you want to delete a folder called “work” and display a message when it is deleted, you can use the command:

rmdir -v work
“-i”: The “-i” flag stands for “interactive” and is used to prompt the user before deleting each directory. For example, if you want to delete a folder called “downloads” but want to confirm each deletion, you can use the command:

rmdir -i downloads

Flags for “mv” command

Here are some common flags for the mv command:

-i: This flag makes mv ask you for confirmation before overwriting an existing file with the same name. For example, if you want to move a file called “report.doc” to the Desktop, but there’s already a file with the same name there, you can use the -i flag like this:
```
mv -i ~/Documents/report.doc ~/Desktop/
```
This will prompt you to confirm whether you want to overwrite the file on the Desktop or not.
-v: This flag makes mv output more information about what it’s doing, so you can see a list of files that have been moved or renamed. For example, if you want to move all the files in a directory called “pictures” to a new directory called “old_pictures” and see a list of what was moved, you can use the -v flag like this:
```
mv -v ~/pictures/* ~/old_pictures/
```
This will show you a list of all the files that were moved.
-n: This flag tells mv not to overwrite any existing files with the same name. For example, if you want to move a file called “report.doc” to the Desktop, but there’s already a file with the same name there, you can use the -n flag like this:
```
mv -n ~/Documents/report.doc ~/Desktop/
```
This will prevent the file on the Desktop from being overwritten.

Remember that flags are always written after the command and before the file or directory names. So the full command would be something like mv [flag] [source] [destination].

Flags for “cp” command

Here are some common flags for the cp command:

-r: This flag is used when you want to copy a directory and its contents. For example, if you have a directory called “pictures” that you want to copy to a new directory called “old_pictures”, you can use the -r flag like this:
```
cp -r ~/pictures ~/old_pictures/
```
This will copy the “pictures” directory and all its contents to the “old_pictures” directory.
-i: This flag makes cp ask you for confirmation before overwriting an existing file with the same name. For example, if you want to copy a file called “report.doc” to the Desktop, but there’s already a file with the same name there, you can use the -i flag like this:
```
cp -i ~/Documents/report.doc ~/Desktop/
```
This will prompt you to confirm whether you want to overwrite the file on the Desktop or not.
-v: This flag makes cp output more information about what it’s doing, so you can see a list of files that have been copied. For example, if you want to copy all the files in a directory called “pictures” to a new directory called “old_pictures” and see a list of what was copied, you can use the -v flag like this:
```
cp -v ~/pictures/* ~/old_pictures/
```
This will show you a list of all the files that were copied.

Remember that flags are always written after the command and before the file or directory names. So the full command would be something like cp [flag] [source] [destination].

\newpage

Putting It All Together

Create a new directory called “file_management” using the mkdir command.

Change into the “file_management” directory using the cd command.

Create three new files using the touch command:

“file1.txt”
“file2.txt”
“file3.txt”

Use the ls command to list the contents of the “file_management” directory. Verify that the three files you created are listed.

Create a new directory called “subdir1” using the mkdir command.

Change into the “subdir1” directory using the cd command.

Create a new file called “subfile1.txt” using the touch command.

Change back to the “file_management” directory using the cd command.

Use the ls command to list the contents of the “file_management” directory. Verify that the “subdir1” directory is listed.

Remove the “subdir1” directory and its contents using the rmdir command with the “-rf” flag.

Use the ls command again to list the contents of the “file_management” directory. Verify that the “subdir1” directory and “subfile1.txt” are no longer listed.

Remove “file2.txt” using the rm command with the “-i” flag.

Use the ls command to list the contents of the “file_management” directory. Verify that “file2.txt” is no longer listed.

Remove “file1.txt” and “file3.txt” using the rm command with the “-f” flag.

Use the ls command one last time to verify that the “file_management” directory is now empty.

\newpage

Vocabulary Review

Terms	Definitions
flag	special option that change how a command works
help flag	provides information about the command and how to use it
touch -a	updates the “access time” of a file
touch -m	updates the “modification time” of a file
rm -r	used to remove a directory and all of its contents
rm -i	used to prompt you for confirmation before removing a file or directory
rm -f	used to remove files or directories without prompting you for confirmation
rm -v	used to show you more information about what’s happening as files or directories are being removed

Review Questions

\begin{enumerate}[1.] \item In the context of Linux commands, what is a “flag”? \begin{enumerate}[(a)] \item A type of file format used in Linux \item A parameter or option used to modify the behavior of a command \item A type of directory in Linux \item A security feature in Linux systems \end{enumerate}

\item What does the command "touch -a" do?
\begin{enumerate}[(a)]
    \item Changes the access timestamp of a file to the current time
    \item Creates a new empty file with the specified name
    \item Modifies the modification timestamp of a file to the current time
    \item Removes a file or directory from the system
\end{enumerate}

\item What does the command "touch -m" do?
\begin{enumerate}[(a)]
    \item Changes the access timestamp of a file to the current time
    \item Creates a new empty file with the specified name
    \item Modifies the modification timestamp of a file to the current time
    \item Removes a file or directory from the system
\end{enumerate}

\item What does the command "rm -r" do?
\begin{enumerate}[(a)]
    \item Removes a file or directory from the system
    \item Renames a file or directory
    \item Recursively removes a directory and its contents
    \item Removes a file or directory with confirmation prompt
\end{enumerate}

\item What does the command "rm -i" do?
\begin{enumerate}[(a)]
    \item Removes a file or directory from the system
    \item Renames a file or directory
    \item Recursively removes a directory and its contents
    \item Removes a file or directory with confirmation prompt
\end{enumerate}

\item What does the command "rm -f" do?
\begin{enumerate}[(a)]
    \item Removes a file or directory from the system
    \item Renames a file or directory
    \item Recursively removes a directory and its contents
    \item Removes a file or directory without confirmation prompt
\end{enumerate}

\item What does the command "rm -v" do?
\begin{enumerate}[(a)]
    \item Removes a file or directory from the system
    \item Renames a file or directory
    \item Recursively removes a directory and its contents
    \item Removes a file or directory and displays the details of the removal operation
\end{enumerate}

\end{enumerate}