What Is the S in Linux File Permissions?
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1 Answer. s (setuid) means set user ID upon execution. If setuid bit turned on a file, user executing that executable file gets the permissions of the individual or group that owns the file. In this s permission was given to owner, so it represents the file is executable and set-user-ID mode is set.

What is difference between S and S in Linux permissions?

On Linux, look up the Info documentation ( info ls ) or online. The letter s denotes that the setuid (or setgid, depending on the column) bit is set. When an executable is setuid, it runs as the user who owns the executable file instead of the user who invoked the program. The letter s replaces the letter x .

What does chmod s do?

Using chmod +s on a directory, changes the user/group as which you “execute” the directory. This implies that, whenever a new file or subdir is created, it will “inherit” the group ownership of the parent directory if the “setGID” bit is set.

Sarah Jenkins

Sarah Jenkins

Senior Technology Editor & AI Specialist

Sarah Jenkins is a veteran tech journalist with over 12 years of experience covering artificial intelligence, mobile innovations, and digital ethics. Her insights have appeared in leading technology publications worldwide.

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