OS lab 4 - 4b "df,du commands"

Working Directory Setup

  • Importance of being in the correct working directory before issuing commands.

Disk Usage Command: df

  • The command df is utilized to output the usage of drives within the specified folder.

  • Focus is on the line that begins with a slash, denoting the root folder of the hard drive.

Key Outputs of df

  • Outputs the following details:

    • Used Bytes: Indicates the number of bytes currently utilized on the drive.

    • Available Bytes: Indicates the number of bytes available for use on the drive.

Improved Readability with -h Option

  • To enhance readability, the command can be modified to df -h.

    • The h stands for "human-readable" format.

    • After executing df -h, outputs example:

    • 14 gigabytes of used hard disk space

    • 39 gigabytes of available disk space

Benefits of Using df -h

  • Provides immediate information about disk space without navigating through a file explorer.

  • Simplifies the process of checking disk space to a single command.

Disk Usage of Folders: du

  • The command du is used to determine the size of all folders in the current directory.

  • du provides insight into what is occupying disk space within the folder.

Enhanced Readability with -h

  • The command can be altered to du -h for a human-readable output on folder sizes.

    • For example, running du -h may show:

    • Lesson Four file is taking 336 KB

    • Total size for the Lesson Four directory is 360 KB

Recursive vs Summary Output

  • By default, du does a recursive evaluation of folder sizes, which includes all subdirectories and files.

  • To get a summarized view, the command can be modified to du -sh:

    • This will return the total size of the current directory.

    • For instance:

    • If executed, it may show the current directory takes 424 KB.

Summary of Disk Usage with Wildcards

  • To examine sizes of all directories, use du -sh *:

    • The asterisk (*) represents all files and directories in the current folder.

    • Example output:

    • Lesson One takes 80 KB

    • Lesson Two takes 12 KB

    • Lesson Four is largest, occupying 360 KB.

Practical Application

  • Utilizing du -sh * can assist in identifying which files or directories occupy substantial disk space.

  • In case of limited disk space, this command allows users to target specific large files or folders for deletion without needing additional software.