chown

summary

This subchapter looks at chown, a UNIX (and Linux) command.

chown

This subchapter looks at chown, a UNIX (and Linux) command.

chown is used to change the owner or group of a file.

The chown command was described in the first UNIX book, UNIX Programmer’s Manual, by Ken Thompson and Dennis Ritchie, published November 3, 1971.

giving away a file

You can use the chown to change the ownership of a file or directory, giving ownership away to someone else.

The following example gives away ownership of the filename to the account newowner.

warning
Just read — do not type
this will give away your file and you have to use root to get it back

$ chown newowner filename

Of course, a system administrator can use root to freely change ownership of files and directories. This is a powerful tool in the hands of a system administrator.

security leak

This command is often limited to only root (or superuser) because if a computer system or server enforces limits on how much disk storage space each account is allowed, someone can set a file so they still can read and write it (and possibly execute it, if applicable), then change ownership to anyone else. This gets the file (or entire directories) out of their storage limits, but they can still make use of the files.

other

On November 8, 2010, Ramesh Natarajan named this the number 33 most frequently used UNIX/Linux command at this web page 50 Most Frequently Used UNIX / Linux Commands (With Examples).

In June 2009, Ken Milberg named this command as one of the Top 50 universal UNIX commands at this web page Top 50 Universal INIX commands. Note that this web page requires agreeing to be spammed before you can read it.