This character is a Other Symbol and is commonly used, that is, in no specific script. The character is also known as command key (1.0) and operating system key (ISO 9995-7).
The glyph is not a composition. It has no designated width in East Asian texts. In bidirectional text it acts as Other Neutral. When changing direction it is not mirrored. The word that U+2318 forms with similar adjacent characters prevents a line break inside it.
The Wikipedia has the following information about this codepoint:
The looped square (⌘), also known as Saint John's Arms, Saint Hannes cross (related to Swedish sankthanskors, Danish johanneskors, and Finnish hannunvaakuna), and as the command-key symbol due to its use on the command key on Apple computer keyboards, is a symbol consisting of a square with outward pointing loops at its corners. It is referred to as a looped square, for example, in works regarding the Mississippian culture (approximately 800 CE to 1600 CE). It is also known as the place of interest sign when used on information signs, a practice that started in Finland in the 1950s, spreading to the other Nordic countries in the 1960s.
It is an ancient symbol used by several cultures, and remains in common use today. It belongs to a class of symbols which are called valknute in Norway.
Representations
System
Representation (click value to copy)
Nº
8984
UTF-8
E2 8C 98
UTF-16
23 18
UTF-32
00 00 23 18
URL-Quoted
%E2%8C%98
HTML hex reference
⌘
Wrong windows-1252 Mojibake
⌘
alias
command key (1.0)
alias
operating system key (ISO 9995-7)
Encoding: EUC_JIS_2004 (hex bytes)
A7 FC
Encoding: EUC_JISX0213 (hex bytes)
A7 FC
Encoding: GB18030 (hex bytes)
81 36 E9 38
Encoding: ISO2022_JP_2004 (hex bytes)
1B 24 28 51 27 7C 1B 28 42
Encoding: ISO2022_JP_3 (hex bytes)
1B 24 28 4F 27 7C 1B 28 42
Encoding: SHIFT_JIS_2004 (hex bytes)
84 9C
Encoding: SHIFT_JISX0213 (hex bytes)
84 9C
Adobe Glyph List
propellor
RFC 5137
\u'2318'
Bash and Zsh inside echo -e
\u2318
C and C++
\u2318
C#
\u2318
CSS
\002318
Excel
=UNICHAR(8984)
Go
\u2318
JavaScript
\u2318
Modern JavaScript since ES6
\u{2318}
JSON
\u2318
Java
\u2318
Lua
\u{2318}
Matlab
char(8984)
Perl
"\x{2318}"
PHP
\u{2318}
PostgreSQL
U&'\2318'
PowerShell
`u{2318}
Python
\u2318
Ruby
\u{2318}
Rust
\u{2318}
Click the star button next to each label to set this representation as favorite or remove it from the favorites. Favorites will be shown initially. (Favorites are stored locally on your computer and never sent over the internet.)