Q. How do I find out the name of file / directory owner under UNIX / Linux operating systems?
A. You can use ls -l command (list information about the FILEs) to find our the file / directory owner and group names.
The -l option is known as long format which displays Unix / Linux / BSD file types, permissions, number of hard links, owner, group, size, date, and filename. In some environments and UNIX versions / Linux distributions, providing the option –color (for GNU ls) or -G (FreeBSD ls) causes ls to highlight different types of files with different colors.
(Fig. 01: Linux file colors)
(Fig. 02: Understanding Linux / UNIX file colors code [ image credit wikipedia] )
How do I find out owner / group name for a file?
Type the ls -l command at a shell prompt:
$ ls -l filename
-rw-r--r-- 1 vivek admin 2558 Jan 8 07:41 filename
- -rw-r–r– : file mode
- 1 – number of links
- vivek – Owner name (if user name is not a known user, the numeric user id displayed)
- admin – Group name (if group name is not a known group, the numeric group id displayed)
- 2558 – number of bytes in the file (file size)
- Jan 8 07:41 – abbreviated month, day-of-month file was
last modified, hour file last modified, minute file last modified
- filename – File name / pathname
ls -l file mode (permissions)
Quoting from the unix ls command man page – the file mode printed under the -l option consists of the entry type and the permissions. The entry type character describes the type of file, as follows:
|b||Block special file.|
|c||Character special file.|
The next three fields are three characters each: owner permissions, group permissions, and other permissions. Each field has three character positions:
- If r, the file is readable; if -, it is not readable.
- If w, the file is writable; if -, it is not writable.
- The first of the following that applies:
- S : If in the owner permissions, the file is not executable and set-user-ID mode is set. If in the group permissions, the file is not executable and set-group-ID mode is set.
- s : If in the owner permissions, the file is executable and set-user-ID mode is set. If in the group permissions, the file is executable and set group-ID mode is set.
- x : The file is executable or the directory is searchable.
- – : The file is neither readable, writable, executable, nor set-user-ID nor set-group-ID mode, nor sticky.
- T : The sticky bit is set (mode 1000), but not execute or search permission.
- t : The sticky bit is set (mode 1000), and is search able or executable.
See ls command man page for more information:
$ man ls
|Category||List of Unix and Linux commands|
|Firewall||Alpine Awall • CentOS 8 • OpenSUSE • RHEL 8 • Ubuntu 16.04 • Ubuntu 18.04 • Ubuntu 20.04|
|Network Utilities||dig • host • ip • nmap|
|OpenVPN||CentOS 7 • CentOS 8 • Debian 10 • Debian 8/9 • Ubuntu 18.04 • Ubuntu 20.04|
|Package Manager||apk • apt|
|Processes Management||bg • chroot • cron • disown • fg • jobs • killall • kill • pidof • pstree • pwdx • time|
|Searching||grep • whereis • which|
|User Information||groups • id • lastcomm • last • lid/libuser-lid • logname • members • users • whoami • who • w|
|WireGuard VPN||Alpine • CentOS 8 • Debian 10 • Firewall • Ubuntu 20.04|