In the Ubuntu system, we often need to create various files to store data, configuration information, or code. There’s a very simple yet practical command called touch that helps us quickly create empty files. Even if you’re a beginner new to Ubuntu, you can easily master its usage.
What is the touch command?¶
The core function of the touch command is to create an empty file. If the specified file does not exist, it will directly generate a new empty file; if the file already exists, it will not modify the file content but update the file’s access time and modification time (this is important, and we’ll elaborate on it later).
Basic Usage: Creating a Single Empty File¶
The simplest usage is to simply follow touch with the filename you want to create. For example:
touch test.txt
This command will create an empty file named test.txt in the current directory. You can use the ls command to check the current directory, and you’ll see this new file.
Creating Multiple Empty Files¶
touch supports creating multiple files at once. Just list the filenames in sequence after the command, separated by spaces:
touch file1.txt file2.txt file3.txt
After execution, three empty files (file1.txt, file2.txt, and file3.txt) will be generated in the current directory.
Creating Files with a Specified Path¶
If you want to place the file in a specific directory (instead of the current directory), you can add the full path before the filename. For example, to create a file named note.txt in the Documents folder:
touch ~/Documents/note.txt
Here, ~ represents the user’s home directory (e.g., /home/your_username), and Documents is a folder under the home directory. If the target folder does not exist, touch will throw an error. In this case, you need to first create the folder using the mkdir command.
What Happens If the File Already Exists?¶
If the file you want to create already exists, the touch command will not overwrite the file content but update the file’s modification time (i.e., the file’s “last modified time” will be set to the current time). For example, if you previously created test.txt with some content, and you run touch test.txt again, the file content remains unchanged, but the modification time will be updated.
Common Issues and Solutions¶
- Insufficient Permissions: If
touchprompts “permission denied” (e.g., creating a file in the/rootdirectory where ordinary users lack permissions), you can usesudoto elevate privileges (but use it cautiously to avoid accidental operations):
sudo touch /root/test.txt
(Note: The /root directory is typically an administrator-only directory; ordinary users are generally not recommended to create files directly inside it unless for special purposes.)
- Non-existent Path: If the target path contains a non-existent folder (e.g.,
touch /home/user/nonexistent/folder/file.txt), it will prompt “No such file or directory”. In this case, create the directory first:
mkdir -p /home/user/nonexistent/folder # The -p parameter creates multi-level directories
touch /home/user/nonexistent/folder/file.txt # Then execute touch
Summary¶
The touch command, although simple, is a “powerful tool” for creating empty files in Ubuntu. Its main features include:
- Quickly create single or multiple empty files;
- Support specifying paths to place files in any directory;
- If the file already exists, only update the timestamp without modifying the content;
- Be mindful of permissions and path validity to avoid operation failures.
Whether you’re creating a diary file, a temporary configuration file in a project, or batch-generating test files, touch can help you complete the task efficiently. Remember its basic syntax, and check permissions or paths when encountering issues.