Learn about the du command and ways to get the total size of files with a given extension.
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Baeldung Author
Hiks Gerganov
Driven by self-improvement and self-sufficiency. Self-motivated and self-disciplined. Dependable. Minimalist perfectionist. Problem solver. Can work on and improve anything related to IT.
Here's what I've written (so far):
Baeldung on Linux
- All
- Administration (44)
- Processes (27)
- Scripting (26)
- Networking (19)
- Security (14)
- Filesystems (14)
- Files (14)
- File Editing (9)
- Installation (7)
- File Viewing (5)
- File Permissions (4)
- File Compression (3)
- Web (2)
- File Searching (1)
List All Available Certificate Authority (CA) SSL Certificates
Filed under Networking, Security
Explore how to list all SSL certificates in the default store of a Linux machine.
How to Print an RFC-3339 Format Date
Explore the RFC-3339 standard and ways to produce dates based on it.
Character Notations and Removing Whitespace While Keeping Line Endings
Filed under File Editing
Learn about removing whitespace while preserving newlines.
The Shell Prompt and How to Correct For Missing Newlines
Filed under Scripting
Explore the reasons for a distorted prompt position and how to work around them.
Differences Between BSD tar and GNU tar and star
Filed under Administration, File Compression
Explore several tar implementations along with their differences and similarities.
World-Writable Directories in Linux
Filed under Administration
Explore fully-open directories in Linux, their behavior, and how to identify them.
Uptime Wars and the htop Easter Egg Exclamation Point
Filed under Processes
Explore the system uptime and its relation to top and htop.
How to List All Executables From $PATH
Filed under Installation
Explore many ways to output the executables within the $PATH environment variable directories.
The requiretty Option of sudo
Filed under Administration
Learn about terminal allocation and the role of requiretty when using sudo.
modprobe and Fixing the “Operation not permitted” Error
Filed under Administration
Explore kernel permissions, the modprobe command, as well as the “Operation not permitted” error when trying to load a module.
Passing Binary Data to Applications Like curl Without Using a File
Filed under Filesystems
Explore ways to supply binary data directly to commands with the primary example of curl.
How to Access Microsoft Windows Administrative Share From Linux
Filed under Administration
Explore browsing Microsoft Windows administrative shares from Linux.
Huge Page Settings and Disabling Huge Pages in Linux
Filed under Administration
Explore the settings of standard and transparent huge pages, as well as how to check their status and disable them completely.
How to Exclude Filesystems When Using find
Filed under Filesystems
Explore ways to limit the filesystems find traverses.
sed Print to Standard Output When Editing In-place
Learn a sed-only way to delete the first line of a file while also printing it with a single command.
Change the Default /tmp Directory to a User-Defined Path
Filed under Filesystems
Explore ways to change the Linux temporary directory path.
Systemd Unit File Permissions
Filed under Administration, File Permissions
Explore unit files and their permissions.
How to Find Files with Non-Printable and Non-ASCII Characters in Their Names
Filed under File Searching
Explore ways to find path elements with names that contain special characters.
Fast Ways to Efficiently Make Multiple Files in Linux
Filed under Files
Explore different ways to generate many files.
Remove All Comments From a Bash Script in the Shell
Filed under Scripting
Explore ways to remove comments from a Bash script.
HTML Parsing for Extracting Text Between HTML Tags in the Shell
Filed under Scripting
Explore ways to extract the content between two HTML tags in the shell.
Network Processes and How to Identify a Process Which Has No PID
Filed under Processes
Learn about network processes and why they might seem to lack a PID.
Owner of a Mounted Partition
Filed under Administration, Filesystems
Learn how to change the owner of a mount point and location.
Universal Unique Identifiers and the Purpose of an UUID for a Network Interface Card
Filed under Networking
Learn about serial numbers, universal unique identifiers, and their role in network interfaces.
Setting ulimit Limits in systemd Units
Filed under Administration
Learn how to set limits within systemd units.
Zero Padding in the Shell
Filed under Scripting
Explore ways to add and remove zero padding in a standard POSIX environment.
NGINX Timeouts and How to Disable Them
Explore NGINX timeouts and their settings.
Check and Change Default Document Root in NGINX
Filed under Administration, Web
Explore ways to check and set NGINX’s default and current document root paths.
How to Send a Signal to a Process Without Killing or Stopping It
Filed under Processes
Explore ways to send a signal that doesn’t stop or terminate a process.
Inspecting TXT Records of a Domain in the Shell
Filed under Networking
Learn about domain TXT records with different tools, exploring some details of the process.
Store Paths and Change Directory With a Variable in the Shell
Filed under Scripting
Explore ways to use shell variables when changing to a new path.
Vi Initialization and Configuration Files
Filed under File Editing
Explore the initialization process of the Vi editor when it comes to settings and configuration files.
CMake and Setting CMAKE_INSTALL_PREFIX
Filed under Installation
Learn about CMake and make to understand how to change options like the installation destination path.
How to Split Only on a Newline in Shell
Filed under Scripting
Explore ways to split text only at newlines in the shell.
Getting and Changing ARP Settings and the Default ARP Cache Timeout
Filed under Networking
Explore the ARP protocol implementation in Linux and focus on its available settings.
Remove and Avoid Duplicate Entries in Bash History
Filed under Administration
Learn about the duplicates in the Bash history list, as well as how to deal with them.
How to Close a TTY?
Filed under Administration
Learn how to close a terminal on several levels.
Storing the Output of watch to a File
Learn about the output of watch and how to capture that in a file.
Toggle Between FTP Active and Passive Modes
Filed under Networking, Processes
Learn how to switch session modes with different FTP clients.
Absolute Paths and Removing Leading Slashes With tar
Filed under File Compression
Explore leading slashes and absolute paths, as well as their consequences when using tar.
Automate FTP Login and Scripting Using the Shell
Filed under Administration, Networking
Learn ways to log in to an FTP, FTPS, and SFTP server automatically.
Basic and Advanced Searching in Vi
Filed under File Viewing
Explore basic and advanced ways to search in Vi.
Is It Safe to Clear the /tmp Temporary Directory?
Filed under Administration, Files
Learn how to remove files from the /tmp directory safely.
Mirroring With wget and Avoiding Parent Directories
Filed under Filesystems
Learn how to handle directory creation while mirroring with wget.
Installing Packages on Debian and Using a URL
Filed under Installation
Learn how to install a Debian package directly from a URL.
The Difference Between sudo -i and sudo su –
Filed under Administration
Learn how three ways to elevate a session differ.
How to Remove the Passphrase From an Existing SSH Key
Filed under Security
Learn how to remove the password from SSH keys via two common SSH suites.
How to Change root Password via sudo Without su
Filed under Administration
Learn about modifying passwords and how to do that for the root user without first using su.
How to Use Shell Variables in an AWK Script
Filed under Scripting
Explore how to pass values of shell variables to AWK for internal use.
Symbolic and Hard Link Modification and Ownership Changes
Filed under Administration, File Permissions
Explore ways to work with links instead of their targets.
How to Use Multiple SSH Private Keys in Linux
Filed under Security
Explore ways to organize the use of multiple private keys with SSH.
Absolute and Relative Symlinks and Moving a Relative Symbolic Link
Filed under File Viewing
Learn a standard way to relocate relative symbolic links without severing the connection with their target.
Getting a Unique Machine Identifier
Filed under Administration
Explore methods to extract an identity from a Linux system.
Convert Text to PDF From the Command Line
Filed under Scripting
Explore ways to convert simple text files to PDF from the command line.
Cleartext Passwords in the Shell and How to Handle Special Characters
Filed under Administration, Scripting
Learn about passwords with special characters and ways to handle them.
System Calls and Library Calls in Linux
Filed under Administration, Processes
Explore system calls, library calls, and how they differ.
How to Compare Local and Remote Directories
Filed under Networking, Processes
Learn how to perform a comparison between a local and a remote directory.
Parsing, Validating, and Printing JSON in Shell Scripts
Filed under Scripting
Explore many ways to handle JSON in the shell.
Line Endings and Resolving the configure: /bin/sh: bad interpreter Error
Explore newlines, how they can affect file processing, and what we can do about it.
Kill a defunct Zombie Process with Parent init PID 1
Filed under Processes
Learn about our options when an initialization process is the parent of a zombie.
How to Check Whether Terminal Can Print Colors
Filed under Administration
Learn if terminal supports colors and ways to detect it.
Character Navigation or How to Jump to a Specific Character in Vi
Filed under File Viewing
Learn about character positioning and how to employ it when moving the cursor.
PDF Tools and How to View and Edit the Code of a PDF File in Linux
Filed under Files
Explore the PDF file format, how to view its contents, as well as tools that can handle and manipulate it under Linux.
Idling and Dummy Executable Files That Do Nothing in Linux
Learn about built-ins, commands, binaries, and other executables that do nothing.
Locales and How to Find Character Encoding of Linux Terminal
Filed under Administration
Learn about locales, how they are used in Linux, and checking the encoding in different environments.
Extend The Session Time for sudo
Filed under Administration
Explore sudo sessions, why we need them, and how to control their lengths.
List Upgradable Packages in Linux
Filed under Installation
Explore ways to check which packages on a given system currently have upgrades.
SSH Key Format Issues and Fixing the “invalid format” Error
Filed under Security
Explore common causes for malformed SSH keys, as well as their consequences.
When kill -9 or kill -SIGKILL Does Not Work
Filed under Processes
Learn why attempting to kill a process might not always succeed and what we can do about it.
How to Manage and Keep Environment Variables When Using sudo
Filed under Administration
Explore ways to work with and preserve the environment of a sudo session.
Force Edit and Save of Opened File Without Permissions in Vi
Filed under File Editing, File Permissions
Explore different ways to preserve our changes and save a file opened without write permissions in Vi.
Changing Indentation Size in Vi
Filed under File Editing
Explore different ways to indent in the Vi editor and how to set the indentation amount.
Are Hostnames Case Sensitive in Linux?
Filed under Networking
Explore types of system identifiers, numeric address to name resolution, and whether the latter is case-sensitive.
Generating Keys Without a Passphrase with OpenSSH, PuTTY, and OpenSSL
Explore how to generate passwordless SSH keys with three common tools.
How to Solve the “sudo: /usr/bin/sudo must be owned by uid 0 and have the setuid bit set” Error
Filed under Administration
Learn how to remedy global permission issues.
Search for Class Files in Multiple JAR Files in Linux
Filed under Filesystems, Installation
Explore one simple and one complex but precise way to search for class files within JAR files under a given directory.
/etc/shadow and Creating yescrypt, MD5, SHA-256, and SHA-512 Password Hashes
Filed under Administration, Security
Explore the /etc/shadow file and its options to set passwords.
Actual Use of the Linux arp Command
Filed under Networking
Explore the arp command along with its options.
Vi Automatic Commands and Reloading the Current File Contents
Filed under File Editing, File Viewing
Learn how to automate commands in Vi.
What Is the /dev/mem File?
Filed under Administration, Files
Look at address space files available in Linux.
Ways to Stop and Restart a Linux system or the Difference Between halt, poweroff, shutdown -H, and shutdown -P
Filed under Administration
Explore usual commands for stopping and restarting a Linux system, some of their history, and their current status quo.
Temporarily or Permanently Disable Every Job Listed in a Crontab
Filed under Administration, Processes
Explore ways to disable cron and anacron tasks, as well as how to reenable them at a later stage.
prlimit and Setting the Maximum File Limit for a Running Process
Filed under Processes
Explore ways to limit resource usage for a given process, with the main example of lowering the maximum number of open file handles.
Unzip Files Bigger Than 4GB
Filed under File Compression
Explore the limits of FAT32 regarding the size of files, how they affect archive extraction, and what we can do to avoid problems.
How to Backup Cron Files
Filed under Administration
Explore the anacron and cron tools, their configuration file structure, and a simple way to back them up.
Manual Network Configuration in Linux and How to Set a Static IP Address
Filed under Administration, Networking
Explore network configuration under many different Linux distributions, with the main goal of setting a static IP address.
Manually Add a User Without Tools Like useradd and adduser
Filed under Administration
Explore steps necessary to create a user manually without the help of useradd and adduser.
How to Allow Only SSH Access Using iptables
Filed under Administration, Networking, Security
Explore the iptables rules for leaving a machine open only to SSH traffic.
Using SSH Name Resolution to Associate Name with IP
Filed under Administration, Networking, Security
Explore ways to use name resolution with SSH.
Automate Commands Upon SSH Connection
Filed under Administration, Networking
Explore ways to execute remote commands when establishing an SSH session with the example of a simple directory change.
SSH Key Types and Formats or How to Convert PuTTY .ppk to OpenSSH Keys Under Linux
Filed under Administration, Security
Explore PuTTY and OpenSSH, their key types and formats, as well as how to convert between them.
SSH Key Comments and Adding a Comment to an Existing Key
Filed under Administration, Security
Learn how to work with public and private key comments via both the OpenSSH and PuTTY toolsets.
What Is the SSH known_hosts File and How to Temporarily Ignore It
Explore the known_hosts file structure and ways to ignore the known hosts from an SSH client.
Authentication Methods and Their Order in SSH
Filed under Networking, Security
Learn about the SSH authentication methods.
SSH Error “permissions are too open” for Private Key File
Filed under Security
Explore SSH key permissions, problems they may cause, and how to correct them.
Find Out Which Partition a File or Directory Is Located On
Filed under Filesystems
Explore ways to get the physical partition a file or directory is located on.
How to Configure SSH for Multiple Ports
Filed under Security
Learn how to start an SSH server on multiple ports.
Edit /etc/sudoers From a Script
Filed under Scripting
Explore sudo, its sudoers plugin, its configuration, and various ways to change it.
How Is /dev/vda Different From /dev/sda?
Filed under Filesystems
Explore the differences between /dev/sda and /dev/vda.
Check if IP Multicast Is Enabled
Filed under Administration, Networking
Explore many ways to check whether multicast is supported and enabled in a given system.
Mapping a Network Share as a Drive Using the Linux CLI
Filed under Networking
Learn about drive mapping and mounting.
How to Disable IPv6 Globally and on a Specific Interface
Filed under Administration, Networking
Explore the most common way to disable IPv6 on modern Linux distributions.
Portable Ways to Get File Size in Bytes
Filed under Files
Learn how to get the true size of a file.
Invalid Paths and How to cd Into a Directory Without Having Permission
Filed under Filesystems
Learn why we might not be able to change into a given directory in Linux.
Force a CIFS Connection to Unmount
Filed under Filesystems
Learn how to forcefully unmount an SMB connection when it’s not responding.
Execute Shell Commands and Silence Them in Vim
Filed under Scripting
Explore ways to run shell commands and suppress their output while preventing session takeover within the Vi editor.
Stripping Leading and Trailing Whitespaces From All Lines in a File in Vim
Filed under File Editing
Learn how to identify whitespaces in the Vi editor.
Displaying the Full Path of the Current File in Vim
Filed under File Viewing
Explore relative and absolute file paths, concentrating on ways to show the full path of the current file in the Vi editor.
ulimit and the Difference Between Soft Limit and Hard Limit
Filed under Filesystems
Learn about soft and hard limits in the context of resource usage restrictions.
Indenting and Turning Off Auto Indent When Pasting Text Into Vi
Filed under File Editing, Scripting
Explore indenting in Vi and ways to avoid problems with automatic indentation and formatting when pasting contents to the editor.
How to Kill a TTY in Linux
Filed under Processes
Learn what comprises a TTY, how it comes to life, and how we can dispose of one.
Kill a Process That Keeps Restarting
Filed under Processes
Explore different ways to kill constantly restarting processes.
Resetting a Broken TTY
Filed under Processes
Learn how to break a terminal and restore an already broken one.
What do PTY and TTY Mean?
Filed under Processes
Explore TTYs, PTYs, and the differences between them.
One Line if-else Condition in Linux Shell Scripting
Filed under Scripting
Explore single-line if-else statements in contrast to their regular multi-line forms.
Show Special Characters in Linux with less
Filed under File Editing
Learn how less could show special characters, as well as the notation it uses to do so.
Why Should Text Files End With a Newline in Linux?
Filed under Files
A quick and practical explanation why newlines are required when working with Linux files.
Overloaded Terminals or How To Kill a Runaway cat in Linux
Filed under Processes
Learn how to handle overburdened terminals with the primary example of a runaway cat command.
Terminal Shortcuts and How to Unfreeze the Terminal After Pressing Ctrl-S
Filed under Administration, Processes
Learn about terminal shortcuts in Linux.
Monitoring Linux File Access With auditd
Filed under Administration, Files
Explore the comprehensive auditd package in Linux.
Attach a Terminal to a Detached Process in Linux
Filed under Processes
Explore the general idea of attached and detached processes.
Linux Bash Equivalent to the Windows Batch Pause
Filed under Processes
Explore ways to get the behavior of the Windows Batch pause in Linux.
What Is “rc” and What Are “rc” Files?
Filed under Filesystems
Explore rc, its meaning, and how it could hint at the contents of a file or directory.
Check and Monitor Active GPU in Linux
Filed under Administration
Explore options to check and monitor the active video card of a Linux system.
Find Out When a Linux System Was Installed
Filed under Administration, Installation
Explore many ways of checking how old a Linux system is.
Efficiently Delete a Large Directory in Linux
Filed under Files
Discuss methods for efficiently deleting a directory in Linux.
Recover Lost and Deleted Data in Linux
Filed under Files, Filesystems
Explore many ways data can be lost, damaged, or deleted and discuss diagnosis, repair, and recovery in all cases.
inotify and Solving the “upper limit on inotify watches reached!” Error
Filed under Processes
Explore the inotify Linux subsystem, used by many applications.
Get External IP Address in a Shell Script
Filed under Networking
Explore how to check a machine’s external IP address via a Bash shell script.
Text Objects in Vim
Filed under File Editing
Learn about text objects and how to use them in the Vi editor.
Using grep on a Continuous Stream
Explore how grep can be used with continuous streams of data.
Linux inodes
Filed under Filesystems
Explore inodes and their major role in filesystems.
Getting Data Locally From a Remote SSH Session in Linux
Filed under Networking, Security
Explore different ways to get data back to the client after and during an SSH session to a server.
Get Bash Script Location From Within the Script
Filed under Scripting
Explore acquiring a Bash script’s location from within the script.
Escaping Characters in Bash
Filed under Scripting
Discuss character escaping in Bash.
Debugging Programs Using the GDB Command
Explore debugging with the GNU Project Debugger.
Setting Command Timeouts in Bash
Filed under Administration
In this tutorial, we’ll see into different ways of using timeouts in Bash.
Understanding and Ignoring Errors in Bash
Filed under Processes
An overview of errors in Bash.
Using 2D Arrays in Bash Under Linux
Filed under Scripting
Explore different Bash implementations for 2D arrays, along with their downsides.
Working With Large Files in Linux
Filed under Files
Learn some common problems and explore tools that help when partially processing huge files
Guide to Desktop Entry Files in Linux
Filed under Files
Learn about what Linux desktop entry files are, why they are useful, and how they function.