Essential Linux Commands Every Embedded Programmer Should Know

In the world of embedded programming, Linux is often the go-to platform for development, debugging, and deployment. Whether you’re working on microcontrollers, system-on-chips (SoCs), or complex embedded systems, a solid grasp of Linux commands is essential. These tools not only simplify the workflow but also provide powerful control over the development environment. In this blog post, we’ll explore some of the most important Linux commands that every embedded programmer should know.

Mastering these Linux commands can significantly improve your efficiency as an embedded programmer. From managing files to debugging and monitoring processes, each of these commands plays a key role in making your development workflow smoother. Whether you’re new to embedded systems or a seasoned developer, having these tools at your fingertips can save you time and headaches.

1 Linux File System

The Linux file system is a hierarchical structure that organizes and manages files and directories in a logical and standardized way. It plays a critical role in how data is stored, accessed, and managed. Here’s an overview of the key components and concepts of the Linux file system:

1.1. Root Directory (/)

The root directory is the starting point of the Linux file system, denoted by a forward slash (/). All other directories and files in the system branch out from this root. The structure of the file system is like an inverted tree, where the root is at the top.

1.2. Standard Directories

The Linux file system adheres to a standardized layout, often referred to as the Filesystem Hierarchy Standard (FHS). Here are some of the important directories you’ll find in almost any Linux system:

• /bin: Essential user command binaries (e.g., ls, cp, mv).
• /sbin: System binaries, containing essential commands for system administration (e.g., shutdown, mount).
• /usr: User-related programs and data, including applications, libraries, documentation, and binaries (e.g., /usr/bin, /usr/lib).
• /var: Variable files such as logs, databases, and temporary data that changes frequently (e.g., /var/log, /var/lib).
• /home: User home directories, where personal files and settings are stored (e.g., /home/username).
• /etc: Configuration files specific to the system (e.g., network settings, user profiles).
• /lib: Essential shared libraries and kernel modules (e.g., /lib/modules).
• /tmp: Temporary files, which may be deleted upon reboot.
• /dev: Device files, representing hardware devices like hard drives, printers, etc.
• /mnt and /media: Mount points for external storage devices (e.g., USB drives, CDs).
• /boot: Files needed for booting the system, including the kernel and bootloader configuration.
• /opt: Optional software packages.
• /proc and /sys: Virtual directories that provide information about system processes and hardware.

1.3. Mounting

Linux treats everything as a file, including devices. Mounting is the process of making a filesystem (on a device like a hard drive or USB stick) accessible at a specific point in the directory tree. The command mount is used to attach file systems, and umount is used to detach them.

1.4. File Types

In Linux, there are several file types:

• Regular files: These are the most common file types, containing data, programs, or text (-).
• Directory files: These contain lists of files (d).
• Symbolic links: These are shortcuts that point to another file or directory (l).
• Special files: Devices are represented as files, including block devices (e.g., hard drives) and character devices (e.g., terminals).

1.5. File System Management

Some key commands to manage and interact with the file system include:

• df: Displays disk space usage.
• du: Shows directory size.
• fsck: Checks the integrity of the file system.
• mount and umount: Mount and unmount file systems.
• mkfs: Creates a new file system on a device.

1.6 File Property

Each file or directory in Linux has detail information or properties

Core Commands

These foundational commands help manage files, directories, and permissions—crucial when working in the embedded space:

1. ls
   Lists files and directories in the current directory. Helpful for navigating file structures, especially in a cross-compiled environment.
2. cd
   Change directories. A basic yet essential command for moving around in the file system.
   • cd /path/to/your/embedded/code
3. cp and mv
   Copy (cp) and move (mv) files—useful for managing binaries, scripts, or configuration files.
   • cp main.c /backup/ mv main.c src/¹
4. chmod
   Adjust file permissions. Embedded systems often have strict permission requirements, especially for executable binaries.
   chmod +x program
5. make
   Executes the Makefile to build your project. This is often part of the standard embedded development workflow.
6. Creating Files Commands : touch, cp, vi
   • cp : copy
     • To copy a directory on Linux, you have to execute the “cp” command with the “-R”option for recursive and specify the source and destination directories to be copied
     • cp -R <source_folder> <destination_folder>
7. Navigating File System
   • When navigating a UNIX filesystem, there are a few important commands:
     • “cd”
     • “pwd”
     • “ls“
   • cd: stands for change directory. It is the primary command for moving you around the filesystem.
   • pwd: stands for print working directory. It tells you where you current location is.
   • ls: stands for list. It lists all the directories/files within a current working directory
   • Using of TAB key to auto-complete
8. find used to search specific files from the system
9. Help Commands
   • There are 3 types of help commands
     • whatis command
     • command –-help
     • man command
10. Adding Text to Files (Redirects)
    • 3 Simple ways to add text to a file
      • vi
      • Redirect command output > or >>
      • echo > or >>
11. Standard Output to a File (tee)
    • “tee” command is used to store and view (both at the same time) the output of any command
    • The command is named after the T-splitter used in plumbing. It basically breaks the output of a program so that it can be both displayed and saved in a file. It does both the tasks simultaneously, copies the result into the specified files or variables and also display the result

12. File Display Commands

Efficiently viewing and manipulating files in the Linux environment is key to embedded programming. These commands help you inspect configuration files, code, or output logs directly from the terminal.

1. cat
   Concatenates and displays the contents of a file. This is a quick way to view the entire file’s contents, which is often helpful for examining logs or configuration files in embedded systems.
   • Example: cat /etc/config_file
2. less
   A pager utility that allows you to scroll through the contents of a file one screen at a time. Unlike cat, less is more efficient for viewing large files such as debug logs.
   • Example: less /var/log/syslog
3. more
   Similar to less, but with more limited functionality. It displays the contents of a file one screen at a time but doesn’t support backward scrolling.
   • Example: more my_large_log.txt
4. head
   Displays the first few lines of a file. This is useful when you only need to check the beginning of a file, such as the header of a log or the start of a configuration file.
   • Example: head -n 10 my_file.txt
5. tail
   Displays the last few lines of a file. Commonly used in embedded systems for monitoring logs in real time (especially during debugging).
   • Example: tail -f /var/log/syslog
6. grep
   Searches for specific patterns within files. In embedded programming, you may often need to search for specific errors or keywords within large log files.
   • Example: grep "error" /var/log/syslog
7. diff
   Compares two files and shows the differences between them. This can be useful in embedded programming to track changes in configuration files or source code.
   • Example: diff config_old.txt config_new.txt
8. xxd
   A hex dump tool that allows you to display the binary contents of a file in hexadecimal. This can be invaluable for embedded developers working with binary data or firmware.
   • Example: xxd firmware.bin
9. od
   Another tool for displaying binary files, but it can also display the content in octal, decimal, or ASCII formats. It is particularly useful for viewing binary output in various forms.
   • Example: od -t x1 my_binary_file.bin

13. File and Text Processing Commands

Working with configuration files, logs, or script outputs is a common task in embedded programming. These Linux commands make it easier to manipulate, search, and process text data.

1. awk
   A powerful text processing tool that is often used for pattern scanning and extracting specific columns of data from files. It’s useful in embedded systems when parsing logs or configuration files. Example: awk '{print $1, $3}' file.txt
   • This command extracts the first and third columns from the file.
2. sed
   Stream editor that allows you to search and manipulate text files. Commonly used for automated edits to files, such as modifying configuration values in embedded systems.
   • Example: sed -i 's/old_value/new_value/' config.txt
   • This command replaces old_value with new_value in the file.
3. cut
   Extracts specific sections from each line of a file. This command is useful when you need to pull out certain parts of a line in log files or data outputs.
   • Example: cut -d':' -f1 /etc/passwd
   • Extracts the first field from the /etc/passwd file, delimited by :.
4. sort
   Sorts the lines in a file. Sorting logs or configuration values can make them easier to analyze in an embedded system.
   • Example: sort my_file.txt
   • This command sorts the file contents alphabetically or numerically.
5. uniq
   Removes duplicate lines from a sorted file. In embedded systems, where logs or output files might have repeating entries, uniq helps clean the data.
   • Example: sort my_file.txt | uniq
   • This command sorts the file and removes duplicates.
6. tr
   Translates or deletes characters in a file. This can be helpful in embedded systems when you need to reformat or clean up log or configuration files.
   • Example: tr 'a-z' 'A-Z' < input.txt > output.txt
   • Converts lowercase letters to uppercase in the input file.
7. wc
   Counts lines, words, and characters in a file. This command can be useful for analyzing the size of logs, outputs, or data files in an embedded system.
   • Example: wc -l my_file.txt
   • This counts the number of lines in the file.
8. tee
   Reads from standard input and writes to both standard output and a file. In embedded systems, this is particularly useful when you want to log command output while still displaying it.
   • Example: make all | tee build.log
   • This command runs make and saves the output to build.log while also displaying it.
9. find
   Searches for files and directories based on certain conditions. It’s useful for locating configuration files, scripts, or logs in embedded systems, especially when navigating large directories.
   • Example: find / -name "*.conf" Finds all files with the .conf extension.
10. xargs
    Executes commands using input from another command, often used with find or grep to perform operations on the results.
    • Example find . -name "*.log" | xargs rm
    • This command finds all .log files and deletes them.

Debugging and Process Management Commands

In embedded systems, efficient debugging and process control are critical. These commands can help you analyze, manage, and optimize your embedded applications.

1. gdb
   The GNU Debugger is one of the most powerful tools available for debugging embedded systems. You can use it to inspect memory, set breakpoints, and step through your code to find bugs. Often used with cross-compilers for embedded targets.
2. strace
   Traces system calls made by a program. This command is invaluable for diagnosing system-level issues, such as file access errors or memory allocation problems in embedded software.
3. top and htop
   These commands display real-time system resource usage. Embedded systems often have limited CPU and memory resources, and these tools help you monitor and manage those.
4. ps
   Lists running processes, which is crucial when debugging processes on an embedded system that might be stuck or consuming too many resources.
5. kill
   Terminates a process by its ID (PID). Embedded systems may require killing processes manually if they become unresponsive.
6. dmesg
   Displays kernel messages. Embedded systems are heavily tied to kernel behavior, and dmesg helps you check for hardware-related logs, such as boot messages or errors related to drivers.
7. lsof
   Lists open files and the processes that are using them. This is useful in embedded systems to detect file handling issues, such as files that are not being closed properly.
8. netstat
   Displays network connections, routing tables, and interface statistics. Embedded devices often involve network communication, and netstat can be used to monitor and debug network traffic.

Conclusions:

Mastering Linux commands is crucial for embedded systems development. Whether you’re navigating file structures, debugging issues, or processing logs, these commands give you fine-grained control over your environment. From essential file operations to powerful debugging tools and text processing utilities, Linux provides an efficient way to manage and optimize embedded systems. By integrating these commands into your daily workflow, you’ll streamline development, improve troubleshooting, and enhance productivity—ensuring smoother deployments and more stable embedded solutions.