How to Use the tail Command in Linux
Linux
30.09.2024
Reading time: 6 min
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Linux is a family of open-source Unix-like operating systems, such as Debian, Ubuntu, CentOS, and many others. When working with these OSes, we would usually use commands to operate the system and perform tasks like reading, writing, or viewing files, creating, and managing folders. System administrators often need to check system log files or read specific files, and the command tail is one of the essential tools for this purpose.
UNIX tail Command
The tail command in Linux complements the cat and head commands used for reading files. While these commands start reading files from the beginning, the tail command reads or monitors files from the end or bottom.
Syntax
The basic syntax to use the tail command in Linux is as follows:
tail [Option] [File Name]Options
The following are a few options that can be used with the Linux tail command:
|
Option |
Description |
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|
Show the output depending on the number of bytes provided. |
|
|
Continue to show output as the file grows, follow the output |
|
|
Output the last specified number of lines instead of 10. |
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Terminate output after process ID when used with the -f option. |
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Skip the header that shows the file name. |
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Add sleep intervals between iterations. |
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Add a header that contains the file name. |
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Open help information related to the command. |
Let’s move forward to check the practical administrative uses of this command.
Basic Use of Linux tail Command
The tail command Linux is commonly used by administrators to monitor the system logs, debug the system by reading the debug.log file, and check the authorization or authentication through the auth.log file. Here are some basic practical examples of using this command in Linux. For demonstration, this blog uses cities.txt and countries.txt files.
Read File
In Linux, files are normally read using the cat command. However, the cat command simply reads and displays the complete file content from the start:
cat cities.txt
In contrast, the command tail in Linux reads the file from the end or bottom. By default, it displays the last 10 rows of the file. To use this command, execute the tail <file-name>:
tail cities.txt
Read File From Specific Line
To start reading a file from the desired line number, simply use +NUM with the command:
tail +60 cities.txtHere, the result displays the entries from line 60 and onward:
Read File with -n Option
To read or display specified numbers of lines from the tail or bottom, utilize the -n <number of lines> argument with the command as shown below:
tail -n 15 cities.txtThe output displays the last 15 lines of the cities.txt file:
Read Multiple Files
Users can also monitor multiple files through the Linux tail command. For this purpose, utilize tail <file1-name> <file2-name> <file3-name> command:
tail cities.txt countries.txtThis command displays the last 10 entries of provided files and also adds the filename in headers before displaying file entries:
Let’s check out the advanced administrative uses of the tail in Linux through the below section.
Advanced Uses of tail Command in Linux
The tail Linux command is more than just viewing the last few lines of the file. It is used for real-time monitoring, managing the output based on bytes, processes, and sleep time intervals. These all advanced options are used to monitor logs and manage the application behaviors.
Let’s check some advanced practical illustrations of the command.
tail Command with -c Option
To get the output by providing the number of the bytes, use the -c <number of bytes> option:
tail -c 50 cities.txtThe below output shows the specified number of bytes from the bottom instead of lines:
tail Command with -v Option
The -v or --verbose option is used to add the header while displaying the result. The header contains the file name. For demonstration, use the tail -v <file-name> command:
tail -v cities.txt
Monitoring Logs with tail -f
Administrators are often needed to monitor the system in real-time, check application behavior, or debug errors. For this purpose, they usually need to view system logs. In Linux, all log files are located in the /var/log directory. To open and view the log directory, utilize the following commands:
cd /var/log
ls
To monitor the logs in real-time, use the -f or --follow argument with the tail:
tail -f /var/log/syslogAs files or logs grow, these are displayed on the screen continuously as shown below:
tail Command with -s Option
Use the -s <time-interval> argument to add the sleep interval between the iteration while monitoring the logs or file in real-time:
tail -f -s 5 /var/log/syslog
tail Command with -q Option
To read or monitor the file in quiet mode or to skip the header while viewing multiple files, utilize the -q option:
tail -q cities.txt countries.txtHere, the output shows the last 10 lines of the cities.txt and countries.txt files but skips the headers of the files:
tail Command with Pipe(|) Operator
The Pipe (|) operator enables us to pass the output of the first command to the second command. It permits the users to use multiple commands at one time. Similarly, the tail Linux can also be used with some other commands such as the grep command to search specific logs or the sort command to sort the order. Moreover, users can use the tail command with Docker logs to see the latest logs from a Docker container.
Let’s go through the following examples for demonstration.
Example 1: Search for the Specific Word From the End
To search the specific words from the end of the file or a specified number of files from the bottom, use the following command:
tail -n 20 cities.txt | grep "Bangor"In this command, the tail extracts the last 20 lines from the file, and then the output is piped out through the pipe operator, and the grep command filters the specified word from the output:
Example 2: Sort the Output in Reverse Order
To sort the output produced from the tail in reverse order, utilize the following command:
tail -n 6 cities.txt | sort -r
Example 3: Monitor the System Logs of Specific Date
To check the logs of a specific date from the log file, first, extract the logs and then filter the log of the date through the grep command:
tail /var/log/syslog | grep "2024-09-22"
Conclusion
The tail command in Linux is a powerful tool for system administrators and Linux users, providing both basic and advanced functionalities for reading and monitoring files. This command reads or monitors the file or system logs from the tail or bottom. The tail command supports options like -f, -c, --verbose, and -q for advanced functionality. It can also be combined with other commands like grep, sort, df, or cat using the pipe (|) operator for extended functionality. By mastering this command, the users can efficiently manage and troubleshoot their Linux systems.
And if you’re looking for a reliable, high-performance, and budget-friendly solution for your workflows, Hostman has you covered with Linux VPS Hosting options, including Debian VPS, Ubuntu VPS, and VPS CentOS.
Linux
30.09.2024
Reading time: 6 min
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Linux
Linux cp Command
Linux has an unlimited set of commands to perform assigned tasks. The Linux cp command is the primary tool and the basis for copying and managing files and directories in this operating system. This function is designed to duplicate files or directories in the same or different location. Armed with this functionality, users have advanced capabilities: from creating backup copies to moving files between directories.
Linux cp command is simple to learn
You can find all the necessary information covered in this tutorial. You will discover how the Linux cp command and cp directory work, as well as its grammatical structures, crucial hints, parameters, settings, and recommended practices. Readers will learn the tricks of the cp command, which will help them become more proficient.
And if you’re looking for a reliable, high-performance, and budget-friendly solution for your workflows, Hostman has you covered with virtual servers with NVMe storage, Linux VPS Hosting options, including Debian VPS, Ubuntu VPS, and VPS CentOS.
The core of the cp command in Linux
The functionality of the command allows users to control the creation of copies. One feature offers overwriting existing files, another is responsible for recursively copying a directory with its entire entities, and the third protects the first data for repeating backups. This command demonstrates more features for specific purposes and user experience during the process.
A key benefit of the cp command is its exceptional accuracy in duplicating files and directories. You can be absolutely sure that the duplicated files are identical to the original ones with all its interior. Therefore, the user can replicate the original file without any changes. The cp command in Linux inherently tells the user a destination directory for storing copies in a specific repository. The command's precision makes it indispensable for both novice and advanced users.
Linux cp syntax
This command consists of the following parameters: source file or directory and destination directory. The basic syntax of the Linux cp command is as follows:
cp [...file/directory-sources] [destination]
Here [file/directory-sources] specifies the files or directories sources to copy, while the [destination] specifies the location to copy the file to.
There are the letter flags to specify the way of creation a replica of files and directories:
-a leaves the first file attributes the same;
-r recursively replicates directories and their interior entities;
-v shows copied files in detail;
-i requires consent to overwrite the file;
-u rewrites new or missing files in the destination directory;
-f forcibly copies without user consent;
-s makes a symbolic link instead of a file replica;
-ra recreates an exact duplicate of a file or directory without changing attributes;
-rf updates or changes a file or directory with the original name in the same place;
-pv (if installed) monitors and shows the time required to complete copying large folders.
How to copy files with the cp command
To make a file copy, apply the cp command in Linux as follows:
cp ./DirectoryA_1/README.txt ./DirectoryA_2
where ./DirectoryA_1/README.txt is the source file, and ./DirectoryA_2 is the destination.
The cp command was originally designed to interact with files. To replicate directories, you must use the -r flag to command that the directory with all its interior entities to be copied recursively. Therefore, you should write cp -r before the directory sources in Linux as follows:
cp -r ./DirectoryA_1/Folder/ ./DirectoryA_2
The cp -r command in Linux will recursively duplicate the Folder directory in ./DirectoryA_1/ as well as all contents in the Folder directory.
For instance, if you need to replicate the whole file contents in DirectoryA_1 with the .txt extension, try following command:
cp ./DirectoryA_1/*.txt ./DirectoryA_2
where ./DirectoryA_1/*.txt matches files with the .txt extension in their names, and the cp command duplicates all those data to the destination.
Best practices of the cp Linux command
To duplicate one unit of information via the Linux cp command, write down the file name and destination directory. For instance, to replicate a file named example.txt to the 'Documents' directory, try the following command:
cp example.txt Documents/
The action leads to creating a file duplicate in the 'Documents' directory with the original name.
To copy multiple files at once, utilize the cp command in Linux, specifying the file names separated by a space. For instance, to duplicate three files named 'file1.txt', 'file2.txt', and 'file3.txt' to the 'Documents' directory, try the following command:
cp file1.txt file2.txt file3.txt Documents/
To replicate a directory with all its interior entities, apply the -r that means cp recursive feature in Linux. For instance, to duplicate a directory named 'Pictures' to the 'Documents' directory, try the following command:
cp -r Pictures Documents/
The action leads to creating a copy of the 'Pictures' directory with all its interior contents in the 'Documents' directory.
To replicate a folder in Linux, you should utilize the -r flag. For instance, to duplicate a folder named 'Pictures' from the existing directory to a folder named 'Photos' in the home directory, try the following command:
cp -r Pictures/ ~/Photos/
The destination folder will be created automatically if none exists. The files in the destination folder will be combined with the core of the source folder if one already exists.
The cp -a feature in Linux leaves unchanged the initial file attributes while copying. Therefore, the duplicates will have the same parameters as their originals. For instance, to replicate a file named 'example.txt' to the 'Documents' directory while leaving unchanged its attributes, try the following command:
cp -a example.txt Documents/
The Linux cp -v function showcases the progress of the duplication. At the same time the user can copy large files while monitoring the process. For instance, to replicate a file named 'largefile.zip' to the 'Downloads' directory while watching the progress, try the following command:
cp -v largefile.zip Downloads/
The -i option requires the consent before overwriting an initial file. to protect against an accidental file rewriting. For instance, to duplicate a file named 'example.txt' to the 'Documents' directory, if a file with the identical name already exists, the cp command will require the consent before rewriting the original file.
Initially, the Linux cp command copies a file or a directory to a default location. The system allows the user to specify any other location for the duplicate file or directory. For instance, to replicate a file named 'example.txt' from the 'Documents' directory to the 'Downloads' directory, try the following command:
cp Documents/example.txt Downloads/
The cp -ra function in Linux is designed to carry out the copying process of directories with all their contents inside. The -r flag gives an order to repeat all the files and directories within an existing location, while the -a flag keeps the initial attributes preserved. Therefore, it is possible to make an exact duplicate of a directory without changing attributes.
For instance, if you apply the command cp -ra /home/user1/documents /home/user2, it will replicate the 'documents' directory with all its entities inside in the 'user2' directory. The new folder will show the identical attributes as the initial item.
The cp -rf feature in Linux is similar to the previous -ra option. The difference between these two functions is that the -f flag rewrites the given files or directories in the destination without requiring consent. Therefore, it is possible to update or replace an item with the identical name in the place of destination.
For instance, if you apply the command cp -rf /home/user1/documents /home/user2, and there is already a 'documents' directory in the 'user2' directory, it will be overwritten with the contents of the 'documents' directory from the 'user1' directory.
Be careful while utilizing the -rf function. Incorrect use of it leads to data loss. Check up twice the destination folder to avoid unwanted rewriting items.
It is simpler to work with files and directories when you use Linux's cp -r capability with the -a and -f settings. Whereas the -rf particle modifies or replaces files and directories, the -ra particle precisely copies a directory and everything within it. You can learn how to handle stuff in this operating system by properly applying these differences.
If you want to monitor and control the process of item duplication, which is not possible with other parameters of the cp command, use the -pv utility.
To install the pv utility on Debian/Ubuntu you need to open the terminal and run the following command:
apt-get install pv
After the installation is complete, verify it by running the following command in the terminal
pv --version
To install the pv utility on CentOS/Fedora, you need to connect the EPEL repository, which contains additional software packages unavailable in the default repositories. Run in the terminal:
yum install epel-release
Then run the following command in the terminal:
yum install pv
After the installation is complete, verify it by running the following command in the terminal:
pv --version
To use this particle with the cp command, you should utilize | symbol. You can use the ~ symbol to indicate the root directory if the full path needs to be specified.
For instance, to replicate a folder named 'Documents' from the root directory to a folder named 'Backup' in the home directory, try the following action:
cp -r Documents/ ~/Backup/ | pv
Example of executed Linux cp command
Conclusion
The cp command, although not an inherently difficult tool to learn, nevertheless provides basic knowledge of using the Linux operating system in terms of managing files and directories. In this tutorial, we tried to show the capabilities of the cp command in Linux from all sides, demonstrating best practices and useful tips of its various parameters. With new knowledge, you will be able to improve your skills in interacting with files and directories in Linux.
The extreme accuracy of the copying process and additional options allow you to solve a wide range of problems. Multifunctionality helps users choose the file management mode and complete tasks efficiently. The command is a prime example of the many capabilities of this operating system, including the cp with progress feature in Linux. Altogether they unlock a potential of the system for novice and advanced users.
Frequently Asked Questions (FAQ)
How to copy files from one directory to another in Linux?
Use the cp command followed by the source path and then the destination path.
Syntax: cp [source_file] [destination_directory]
Example: cp /home/user/downloads/photo.jpg /home/user/pictures/
What are the most common cp command options?
-r (Recursive): Essential for copying directories. It copies the folder and every file inside it.
-i (Interactive): Prompts you for confirmation before overwriting an existing file. Highly recommended for beginners.
-v (Verbose): Prints the name of each file as it is copied, so you can see the progress.
-p (Preserve): Preserves the original file attributes like modification time, access time, and ownership modes.
How do I copy a directory (folder)?
You must use the -r (recursive) flag. If you try to copy a folder without it, Linux will give you an error saying the source is a directory.
Command: cp -r source_folder/ destination_folder/
How do I copy multiple files at once?
You can list multiple source files before the destination directory, or use wildcards.
List: cp file1.txt file2.txt /backup/
Wildcard: cp *.jpg /home/user/images/ (Copies all JPG files).
How do I prevent cp from overwriting existing files?
Use the -n (no clobber) flag. This tells Linux to silently skip any files that already exist in the destination folder, rather than replacing them. cp -n file.txt /backup/
What is the difference between cp -u and cp -n?
-n never overwrites.
-u (Update) only overwrites if the source file is newer than the destination file, or if the destination file is missing. This is useful for syncing folders.
22 January 2026 · 10 min to read
Linux
Using the ps aux Command in Linux
Effective system administration in Linux requires constant awareness of running processes. Whether diagnosing performance bottlenecks, identifying unauthorized tasks, or ensuring critical services remain operational, the ps aux command is an indispensable tool.
This guide provides a comprehensive exploration of ps aux, from foundational concepts to advanced filtering techniques, equipping you to extract actionable insights from process data.
And if you’re looking for a reliable, high-performance, and budget-friendly solution for your workflows, Hostman has you covered with Linux VPS Hosting options, including Debian VPS, Ubuntu VPS, and VPS CentOS.
Prerequisites
To follow the tutorial:
Deploy a Linux cloud server instance at Hostman
SSH into the server instance
Understanding Processes in Linux
Before we explore the ps aux command, let's take a moment to understand what processes are in the context of a Linux system.
What are Processes?
A process represents an active program or service running on your Linux system. Each time you execute a command, launch an application, or initiate a background service, you create a process.
Linux assigns a unique identifier, called a Process ID (PID), to each process. This PID allows the system to track and manage individual processes effectively.
Why are Processes Grouped in Linux?
Linux employs a hierarchical structure to organize processes. This structure resembles a family tree, where the initial process, init (or systemd), acts as the parent or ancestor.
All other processes descend from this initial process, forming a parent-child relationship. This hierarchy facilitates efficient process management and resource allocation.
The ps Command
The ps (process status) command provides a static snapshot of active processes at the moment of execution. Unlike dynamic tools such as top or htop, which update in real-time, ps is ideal for scripting, logging, or analyzing processes at a specific point in time.
The ps aux syntax merges three key options:
a: Displays processes from all users, not just the current user.
u: Formats output with user-oriented details like CPU and memory usage.
x: Includes processes without an attached terminal, such as daemons and background services.
This combination offers unparalleled visibility into system activity, making it a go-to tool for troubleshooting and analysis.
Decoding the ps aux Output
Executing ps aux generates a table with 11 columns, each providing critical insights into process behavior. Below is a detailed explanation of these columns:
USER
This column identifies the process owner. Entries range from standard users to system accounts like root, mysql, or www-data. Monitoring this field helps detect unauthorized processes or identify which users consume excessive resources.
PID
The Process ID (PID) is a unique numerical identifier assigned to each task. Administrators use PIDs to manage processes—for example, terminating a misbehaving application with kill [PID] or adjusting its priority using renice.
%CPU and %MEM
These columns display the percentage of CPU and RAM resources consumed by the process. Values above 50% in either column often indicate performance bottlenecks. For instance, a database process consuming 80% CPU might signal inefficient queries or insufficient hardware capacity.
VSZ and RSS
VSZ (Virtual Memory Size) denotes the total virtual memory allocated to the process, including memory swapped to disk.
On the other hand, RSS (Resident Set Size) represents the physical memory actively used by the process.
A process with a high VSZ but low RSS might reserve memory without actively utilizing it, which is common in applications that preallocate resources.
TTY
This field shows the terminal associated with the process. A ? indicates no terminal linkage, which is typical for background services like cron or systemd-managed tasks.
STAT
The STAT column reveals process states through a primary character + optional attributes:
Primary States:
R: Running or ready to execute.
S: Sleeping, waiting for an event or signal.
I: Idle kernel thread
D: Uninterruptible sleep (usually tied to I/O operations).
Z: Zombie—a terminated process awaiting removal by its parent.
Key Attributes:
s: Session leader
N: Low priority
<: High priority
For example, a STAT value of Ss denotes a sleeping session leader, while l< indicates an idle kernel thread with high priority.
START and TIME
START indicates the time or date the process began. Useful for identifying long-running tasks.
TIME represents the cumulative CPU time consumed since launch. A process running for days with minimal TIME is likely idle.
COMMAND
This column displays the command or application that initiated the process. It helps identify the purpose of a task—for example, /usr/bin/python3 for a Python script or /usr/sbin/nginx for an Nginx web server.
Advanced Process Filtering Techniques
While ps aux provides a wealth of data, its output can be overwhelming on busy systems. Below are methods to refine and analyze results effectively.
Isolating Specific Processes
To focus on a particular service—such as SSH—pipe the output to grep:
ps aux | grep sshd
Example output:
root 579 0.0 0.5 15436 5512 ? Ss 2024 9:35 sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups
root 2090997 0.0 0.8 17456 8788 ? Ss 11:26 0:00 sshd: root@pts/0
root 2092718 0.0 0.1 4024 1960 pts/0 S+ 12:19 0:00 grep --color=auto sshd
This filters lines containing sshd, revealing all SSH-related processes. To exclude the grep command itself from results, use a regular expression:
ps aux | grep "[s]shd"
Example output:
root 579 0.0 0.5 15436 5512 ? Ss 2024 9:35 sshd: /usr/sbin/sshd -D [listener] 0 of 10-100 startups
root 2090997 0.0 0.8 17456 8788 ? Ss 11:26 0:00 sshd: root@pts/0
Sorting by Resource Consumption
Identify CPU-intensive processes by sorting the output in descending order:
ps aux --sort=-%cpu | head -n 10
Example output:
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
mysql 1734280 0.4 36.4 1325172 357284 ? Ssl Jan30 87:39 /usr/sbin/mysqld
redis 1424968 0.3 0.6 136648 6240 ? Ssl Jan18 112:25 /usr/bin/redis-server 127.0.0.1:6379
root 1 0.0 0.6 165832 6824 ? Ss 2024 5:51 /lib/systemd/systemd --system --deserialize 45
root 2 0.0 0.0 0 0 ? S 2024 0:00 [kthreadd]
root 3 0.0 0.0 0 0 ? I< 2024 0:00 [rcu_gp]
root 4 0.0 0.0 0 0 ? I< 2024 0:00 [rcu_par_gp]
root 5 0.0 0.0 0 0 ? I< 2024 0:00 [slub_flushwq]
root 6 0.0 0.0 0 0 ? I< 2024 0:00 [netns]
root 8 0.0 0.0 0 0 ? I< 2024 0:00 [kworker/0:0H-events_highpri]
Similarly, you can sort by memory usage to detect potential leaks:
ps aux --sort=-%mem | head -n 10
Example output:
USER PID %CPU %MEM VSZ RSS TTY STAT START TIME COMMAND
mysql 1734280 0.4 36.4 1325172 357284 ? Ssl Jan30 87:39 /usr/sbin/mysqld
root 330 0.0 4.4 269016 43900 ? S<s 2024 22:43 /lib/systemd/systemd-journald
root 368 0.0 2.7 289316 27100 ? SLsl 2024 8:19 /sbin/multipathd -d -s
root 1548462 0.0 2.5 1914688 25488 ? Ssl Jan23 2:08 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
root 1317247 0.0 1.8 1801036 17760 ? Ssl Jan14 22:24 /usr/bin/containerd
root 556 0.0 1.2 30104 11956 ? Ss 2024 0:00 /usr/bin/python3 /usr/bin/networkd-dispatcher --run-startup-triggers
root 635 0.0 1.1 107224 11092 ? Ssl 2024 0:00 /usr/bin/python3 /usr/share/unattended-upgrades/unattended-upgrade-shutdown --wait-for-signal
root 2090997 0.0 0.8 17456 8788 ? Ss 11:26 0:00 sshd: root@pts/0
root 2091033 0.0 0.8 9936 8480 pts/0 Ss 11:26 0:00 bash --rcfile /dev/fd/63
Real-Time Monitoring
Combine ps aux with the watch command to refresh output every 2 seconds:
watch -n 2 "ps aux --sort=-%cpu"
This provides a dynamic view of CPU usage trends.
Zombie Process Detection
Zombie processes, though largely harmless, clutter the process list. Locate them with:
ps aux | grep 'Z'
Persistent zombies often indicate issues with parent processes failing to clean up child tasks.
Practical Use Cases
Now, let’s explore some common use cases of the ps aux command in Linux:
Diagnosing High CPU Usage
Follow the below steps:
Execute this command to list processes by CPU consumption.
ps aux --sort=-%cpu
Identify the culprit—for example, a malfunctioning script using 95% CPU.
If unresponsive, terminate the process gracefully with:
kill [PID]
Or forcibly with:
kill -9 [PID]
Detecting Memory Leaks
Simply do the following:
Sort processes by memory usage:
ps aux --sort=-%mem
Investigate tasks with abnormally high %MEM values.
Restart the offending service or escalate to developers for code optimization.
Auditing User Activity
List all processes owned by a specific user (e.g., Jenkins):
ps aux | grep ^jenkins
This helps enforce resource quotas or investigate suspicious activity.
Best Practices for Process Management
Let’s now take a quick look at some best practices to keep in mind when managing Linux processes:
Graceful Termination: Prefer kill [PID] over kill -9 to allow processes to clean up resources.
Log Snapshots: Periodically save process lists for audits:
ps aux > /var/log/process_audit_$(date +%F).log
Contextual Analysis: A high %CPU value might be normal for a video encoder but alarming for a text editor. Hence, it’s essential to consider the context when making an analysis.
Common Pitfalls to Avoid
Here are some pitfalls to look out for when using ps aux in Linux:
Misinterpreting VSZ: High virtual memory usage doesn’t always indicate a problem—it includes swapped-out data.
Overlooking Zombies: While mostly benign, recurring zombies warrant investigating parent processes.
Terminating Critical Services: Always verify the COMMAND field before using kill to avoid disrupting essential services.
Conclusion
The ps aux command is a cornerstone of Linux system administration, offering deep insights into process behavior and resource utilization. You can diagnose performance issues, optimize resource allocation, and maintain system stability by mastering its output interpretation, filtering techniques, and real-world applications.
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For further exploration, consult the ps manual (man ps) or integrate process monitoring into automated scripts for proactive system management.
Frequently Asked Questions (FAQ)
What is the ps aux command in Linux?
It is the most common command to view a snapshot of all running processes on the system. The flags break down as follows:
a: Shows processes for all users, not just the current user.
u: Displays the process's user/owner and provides detailed resource usage (CPU, RAM).
x: Shows processes not attached to a terminal (background daemons).
Why do we use the ps command in Linux?
We use it to monitor system health and troubleshoot performance. It helps you identify which applications are consuming the most CPU or Memory, find the Process ID (PID) needed to stop a frozen program, and verify if background services are running correctly.
How do you use the ps aux command to find zombie processes?
Zombie processes (defunct) appear with a Z in the STAT column. You can filter for them specifically by running: ps aux | grep 'Z' Alternatively, to get a cleaner list excluding the grep command itself:
ps aux | awk '$8=="Z" {print $0}'
How do I sort the output by Memory or CPU usage?
By default, ps aux does not sort by usage. You can use the --sort option:
Sort by Memory: ps aux --sort=-%mem
Sort by CPU: ps aux --sort=-%cpu (The minus sign sorts in descending order).
What do the VSZ and RSS columns mean?
VSZ (Virtual Memory Size): The total virtual memory available to the process (including swap and shared libraries).
RSS (Resident Set Size): The actual physical RAM the process is currently using. RSS is usually the more important number for checking memory usage.
How do I kill a process I found using ps aux?
First, locate the PID (Process ID) in the second column of the output. Then run: sudo kill [PID] If the process refuses to close, you can force kill it with sudo kill -9 [PID].
22 January 2026 · 10 min to read
Linux
How to Create a Text File in Linux Terminal
In Linux, you can access and edit text files using a text editor that is designed to work with plain text. These files are not specifically coded or formatted.
Choose your server now!
There are several different ways to create a file in Linux. The Linux Command Line or Terminal is most likely the fastest. This is a crucial skill for any user, but especially for server administrators, who need to create text files, scripts, or configuration files quickly for their jobs.
Let's proceed to the guide on four standard techniques for creating a text file on the terminal.
And if you’re looking for a reliable, high-performance, and budget-friendly solution for your workflows, Hostman has you covered with Linux VPS Hosting options, including Debian VPS, Ubuntu VPS, and VPS CentOS.
File Creation in Linux Can be Frustrating Sometimes
Prerequisites for File Creation in Linux
Ensure these prerequisites are met before generating files in a Linux environment using the command-line interface:
Access to a Functional Linux System: You must either have a Linux-based operating system installed on your computer or secure access to a Linux server via SSH (Secure Shell) protocol.
Operational Terminal Interface: Confirm that your terminal application is accessible and fully operational. The terminal serves as your primary gateway to executing commands.
Adequate User Permissions: Verify you can create files within the chosen directory. You may need to use sudo (for directories with access restrictions) to escalate privileges.
Fundamental Commands Proficiency: You must get familiar with essential commands, such as touch for file creation, echo for printing text, cat for viewing file contents, and text editors like nano, vim, or vi for editing files directly.
Text Editing Utilities: Ensure your system includes text editing tools: nano for command line simplicity, vim for advanced configurations, or graphical options like gedit for user-friendly navigation.
Directory Management Expertise: Develop familiarity with directory navigation commands like cd for changing the working directory and ls for listing directory contents. This knowledge streamlines your workflow and avoids potential errors.
Using the touch Command
Generally, we use the touch command to create empty files and change timestamps. It will create an empty file if it doesn't exist already.
To create a text file in the current directory with the touch command:
Open your terminal emulator.
Type the command:
touch filename.txt
Start with "touch" command
Replace "filename" with the name you picked for the file. If the file with the same name already exists, the access and modification timestamps will be updated without affecting the content of the file. If not, a blank file with the specified name will be generated.
Press Enter—if it is successful, there will be no output.
Use the ls command to list the directory content and verify file creation.
"LS" command is also important of you want to generate text file in Linux
Using the echo Command Redirection
The echo command is widely used to display text on the terminal. But its capabilities go beyond that; it may also be used to write content to a file or create an empty file. For this, combine the echo command with double redirect symbols (you can also use a single >) and the desired filename.
A text file can be created by redirecting the output of the echo command to a file. See how it works:
Open your terminal emulator.
Type the command:
echo “Your text content here” > filename.txt
"Echo" command is also important in the process
Replace the text in double quotations (do not delete them) with yours to add it to the file.
After you press Enter, your text will be added to the file filename.txt. It will overwrite an existing file, if there is one. Otherwise, it will just create a new one.
Press Enter.
To verify that the file has been created and contains the desired content, use cat command to display the content.
"Cat" command can help you to display your file you just created
Using the cat Command Redirection
In Linux, the cat command is mostly used to concatenate and show file contents. It can, however, also be used to generate a text document by redirecting the standard output of cat to a file.
Open your terminal emulator.
Type the following command:
cat > filename.txt
This is what you'll see after "cat" command
Replace filename.txt with the name for your text file. This command instructs cat to receive input rom the terminal and to redirect it into the filename.txt.
Press Enter. The terminal will be waiting for input.
Enter the text you want in the file. Press Enter after each line.
Press Ctrl + D when you are done. This signals the end of input to the cat and saves the content.
Run the cat command to check that the file has been created and contains the desired content.
This is how you can check how your file in Linux is created
Using printf for Advanced File Creation
The printf utility is a powerful alternative to echo, offering enhanced formatting options for structuring text. It allows users to create files with precisely formatted content.
Open the terminal.
Use printf to define the text layout, incorporating formatting elements like newlines (\n) or tabs (\t). Redirect the output to a file using the > operator.
Example:
printf "First Line\nSecond Line\nIndented\tThird Line\n" > formatted_file.txt
Run the cat command to inspect the file's content and ensure the formatting matches expectations.
Append Without Overwriting: To add content to an existing file without overwriting its current data, replace > with the append operator >>:
printf "Additional content here.\n" >> formatted_file.txt
Using a Text Editor
You can also create new files in linux text editors. There is always at least one integrated command-line text editor in your Linux distribution. But you can choose and install a different one according to your preferences, for example, Vim, Nano, or Emacs. Each of them has its own features and advantages.
Vim
vim, which stands for "Vi IMproved," is a very flexible and adaptable text editor. It is well-known for its modal editing, which allows for distinct modes for various functions like text entry, navigation, and editing. It allows split windows, multiple buffers, syntax highlighting, and a large selection of plugins for extra features. To create a text file using vim, follow the steps below:
Open vim, with the desired filename as an argument.
"Vim" command is one of the key steps in file creation
Press i to switch to Insert mode.
Start typing and editing the filename.txt.
To save and exit, press Esc to ensure that command mode is running. Type: wq (write and quit) and press Enter.
Simple command to finish your work
Nano
nano is ideal for short adjustments and straightforward text files because it is lightweight and requires little setup. It provides support for basic text manipulation functions, search and replace, and syntax highlighting. To create a text file using nano, follow the steps below:
Run nano with the desired filename as an argument. It will open a new buffer for editing the file filename.txt.
Nano is useful in you want to fix something in your text file
Start typing and editing the filename.txt.
To save and exit, press Ctrl + O to write the file, confirm the filename, and then press Ctrl + X to exit Nano.
Click "yes" to exit
Emacs
emacs is a powerful and flexible text editor that supports syntax highlighting, multiple buffers, split windows, and integration with external tools and programming languages. To create a text file using emacs, follow the steps below:
Open emacs, with the desired filename as an argument.
Start typing and editing the filename.txt.
"Emacs" is more flexible text editor
To save and exit, press Ctrl + X, followed by Ctrl + S to save the file, and then Ctrl + X, followed by Ctrl + C to exit Emacs.
Note: If a message states that "VIM command not found", "nano command not found" or "emacs command not found" in Linux, it typically means that the vim, nano or emacs text editor is not installed on the system, or it's not included in the PATH environment variable, which is a list of directories where the operating system looks for executable files.
Don't forget to install necessary command in Linux
To resolve this, install the text editor first using the command:
apt-get install vim
apt-get install nano
apt-get install emacs
Gedit
An intuitive text editor that supports working with plain text and has syntax highlighting for programming languages. A straightforward graphical interface makes it usable for various tasks, from quick edits to complex document preparation.
Open the Gedit Application: Launch Gedit either through the applications menu or by executing the following command in the terminal:
gedit example.txt
Gedit will create a new file if the specified one does not exist.
Input Your Text: Type or paste your desired content into the editor.
Save the File: Save your work with Ctrl + S or select File > Save. If creating a new file, specify a filename and a location.
Verify: Return to the terminal and confirm the file exists with the ls command or review its content with cat.
Linux File Creation Recommendations
Ensure you have sufficient permissions to create files in the target directory. If they are insufficient, consider working in a directory where you have full rights (or elevate privileges with sudo).
Check if a file with the identical name is already present before using the > operator, as the command will overwrite existing content. To prevent data loss, opt for the append operator >>.
Familiarize yourself with the printf, echo, and text editors like vim or nano. These tools will help you reduce errors when working with files in Linux, as well as boost productivity.
Use printf for creating files requiring structured content, such as configuration files or scripts with precise formatting needs.
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Conclusion
Now you have acquainted yourself with the fundamental skill of creating a file in Linux using the terminal! Using the Linux command line, several fast and efficient methods exist to create and manage text files. Apply several techniques to meet a different requirement using the touch, echo, cat, printf commands, or text editors like vim, nano, gedit, or emacs. Users can select the method that sufficiently meets their requirements, such as creating empty files, appending text, or significantly modifying material. In summary, any of these methods enable Linux users to easily and quickly handle text files straight from the command line.
Frequently Asked Questions (FAQ)
How do I create an empty text file in Linux?
The standard command is touch. Simply run: touch filename.txt This creates a blank file immediately.
How do I create a file and add content at the same time?
You can use the echo command with the redirection operator (>). echo "Hello World" > filename.txt This creates the file and puts "Hello World" inside it.
How do I create and open a file for editing?
Use a terminal text editor like nano or vi. When you run: nano filename.txt Linux will open a blank editor screen. Once you type your text and save (Ctrl+O in nano), the file is created on your disk.
What is the fastest way to create a file?
The redirection symbol alone is the quickest method for creating an empty file:> filename.txt This tells the shell to redirect "nothing" into a new file, creating it instantly.
How do I create a large file for testing?
Use the fallocate command. For example, to create a 1GB file instantly:fallocate -l 1G bigfile.img
How do I view the content of a text file?
Use the cat command to print the text to your terminal: cat filename.txtFor longer files, use less filename.txt to scroll through pages.
21 January 2026 · 10 min to read
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