For questions concerning specifics about the files on Ubuntu. If your question is about the file manager called "Files" in Ubuntu, use the [nautilus] tag instead.
In Linux "everything is a file" (unless it's a process) but files come in different types, most commonly "regular" files, directories (lists of files) and links (to other files). Executable binaries and scripts, text and media files are all regular files.
Types of files with symbols as in the output of ls -l:
| Symbol | Meaning |
|---|---|
- |
Regular file |
d |
Directory |
l |
Symbolic link |
b |
Block device |
c |
Character device |
s |
Socket |
p |
Named pipe |
Each file is linked to a numbered inode that stores metadata about it:
- File type
- Owner id and group id
- Mode: permissions for owner, group and others
- Timestamps of when the file was last accessed and when the inode and file were last changed
- The number of links to the inode
- The file's size
- An address pointing to the blocks where data in the file is located
