About DEL

Integer ASCII code: 127
Binary code: 0111 1111
Octal code: 177
Hexadecimal code: 7F
Group: control
Seq: ^?

Unicode symbol: , int code: 9249 (html &#9249) hex code: 2421 (html &#x2421)


Delete key can't be technically called a part of the C0 control character range. Initially it was used in order to designate previously erased characters on paper tape, because any character could be changed to all ones by punching holes in any place. On VT100 compatible terminals, this is the character produced by the key marked ⌫ . On modern machines it is called backspace and doesn't match the PC delete key.

Sometimes the delete character is also called a rubout. In computing it is the last character in the ASCII repertoire, having the code of 127 (decimal). Being a control character instead of a graphic one, in caret notation it's designated as ^? and has a graphic representation of ␡ in Unicode (because all ASCII control characters have their own graphic representations).

On modern systems terminal emulators it usually turn keys designated as "Delete" or "Del" into an escape sequence like ^~. Terminal emulators may produce DEL when ← Backspace key or Control+← Backspace or Control+? are being typed. Some other programs, for example Notepad insert this character using the same keys.


Initially this code was used in order to mark the characters that were deleted on punched tape, because any character could be changed to all ones just by punching holes in any place. In cases, when a character was punched mistakenly, punching out all seven bits made this position to be ignored or even deleted, a computer version of correction fluid. In hexadecimal, this is 7F to rubout 7 bits, and FF to rubout 8 bits. Lines were usually ended up by the three characters CR, LF, and rubout for teleprinters, for example Teletype Model 33. The rubout left some time in order for the print mechanism to physically move to the left margin. On VT100 compatible terminals, the Delete key generated this character. It transmits a delete character (octal 177, hexadecimal 7F) to the host system. On VT510 compatible terminals, this character is generated by the key designated ?, On modern machines it is commonly called backspace, and doesn't match the PC "Delete" key.

Current use

Unix-like operating systems are widely used it in the role of the clean up control character. In plain words, it's function is to delete the previous character in the line mode. However, it differs from its initial function where this code physically replaced characters on a punched tape to be deleted.

Unlike Unix, DOS/Windows haven't even tried to use this character in any function. Instead of it, Windows used backspace (0x08, or control-H) in order to delete the previous character. EGA/VGA fonts, being fonts that are used by Win32 console, usually have the "house" symbol ⌂ at 127 (0x7F) code point (see Code page 437 for details). Nevertheless, the heritage of it can be seen in some applications that can be considered as a part of the Windows operating system. Let's see an example: typing the Control and ← Backspace key combination in Microsoft Notepad will product the delete character.


input value base type output hash
DEL char MD5 83acb6e67e50e31db6ed341dd2de1595
DEL char SHA1 23833462f55515a900e016db2eb943fb474c19f6
127 dec MD5 ec5decca5ed3d6b8079e2e7e7bacc9f2
127 dec SHA1 008451a05e1e7aa32c75119df950d405265e0904
01111111 bin MD5 b979b632218272f114633bb8697e0c67
01111111 bin SHA1 32e18ade36300a69f281970ca991a113c364c073
0111 1111 bin MD5 316064b28584b8ffa4e1810c6a56824c
0111 1111 bin SHA1 03b63e15a426edd0a95c29cb90fb6185dd80f8d7
177 oct MD5 96da2f590cd7246bbde0051047b0d6f7
177 oct SHA1 26e7458dc56ab2830fadba7bd2c1aa10e981518d
7F hex MD5 e0fb29c277351bded7c7591a7a7e669f
7F hex SHA1 ca90b2acb438835612c69657b6e9897b7655e129
0x7F hex MD5 96833bbd570cc586c447fb97921b949d
0x7F hex SHA1 efaaf84061d00cbedb818492434e308782eb39ae
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 2018 © Dmytro Koshovyi. Ukraine, Mykolayiv.