Editing ANSI escape code (section)

== Fe Escape sequences ==

If the [[#ESC|{{code|ESC}}]] is followed by a byte in the range 0x40 to 0x5F, the escape sequence is of type {{code|Fe}}. Its interpretation is delegated to the applicable [[C0 and C1 control codes|C1 control code]] standard.<ref name="ECMA-35"/>{{Rp|13.2.1}} Accordingly, all escape sequences corresponding to C1 control codes from ANSI X3.64 / ECMA-48 follow this format.<ref name="ECMA-48"/>{{Rp|5.3.a}}

The standard says that, in 8-bit environments, the control functions corresponding to type {{code|Fe}} escape sequences (those from the set of [[C1 control codes]]) can be represented as single bytes in the 0x80–0x9F range.<ref name="ECMA-48"/>{{Rp|5.3.b}} This is possible in character encodings conforming to the provisions for an 8-bit code made in ISO 2022, such as the [[ISO 8859]] series. However, in character encodings used on modern devices such as [[UTF-8]] or [[CP-1252]], those codes are often used for other purposes, so only the 2-byte sequence is typically used. In the case of UTF-8, representing a C1 control code via the [[C1 Controls and Latin-1 Supplement]] block results in a different two-byte code (e.g. {{tt|0xC2,0x8E}} for {{tt|U+008E}}), but no space is saved this way.

{| class="wikitable"
|+ Some type {{tt|Fe}} (C1 set element) ANSI escape sequences (not an exhaustive list)
|-
! Code!!C1!!Abbr!!Name!!Effect
|- id=SS2
| {{tt|ESC N}}
| {{tt|0x8E}}
| {{tt|SS2}}
| Single Shift Two
| rowspan=2 | Select a single character from one of the [[ISO/IEC 2022#Code structure|alternative character sets]]. SS2 selects the G2 character set, and SS3 selects the G3 character set.<ref name="xtc"/> In a 7-bit environment, this is followed by one or more GL bytes (0x20–0x7F) specifying a character from that set.<ref name="ECMA-35"/>{{Rp|9.4}} In an 8-bit environment, these may instead be GR bytes (0xA0–0xFF).<ref name="ECMA-35"/>{{Rp|8.4}}
|- id=SS3
| {{nobr|{{tt|ESC O}}}}
| {{tt|0x8F}}
| {{tt|SS3}}
| Single Shift Three
|- id=DCS
| {{tt|ESC P}}
| {{tt|0x90}}
| {{tt|DCS}}
| Device Control String
| Terminated by ST.<ref name="ECMA-48"/>{{Rp|5.6}} Xterm's uses of this sequence include defining User-Defined Keys, and requesting or setting Termcap/Terminfo data.<ref name="xtc"/>
|- id=CSI
| {{tt|ESC [}}
| {{tt|0x9B}}
| {{tt|CSI}}
| [[#CSIsection|Control Sequence Introducer]]
| Starts most of the useful sequences, terminated by a byte in the range 0x40 through 0x7E.<ref name="ECMA-48"/>{{Rp|5.4}}
|- id=ST
| {{tt|ESC \}}
| {{tt|0x9C}}
| {{tt|ST}}
| String Terminator
| Terminates strings in other controls.<ref name="ECMA-48"/>{{Rp|8.3.143}}
|-
| {{tt|ESC ]}}
| {{tt|0x9D}}
| {{tt|OSC}}
| [[#OSC|Operating System Command]]
| Starts a control string for the operating system to use, terminated by ST.<ref name="ECMA-48"/>{{Rp|8.3.89}}
|- id=SOS
| {{tt|ESC X}}
| {{tt|0x98}}
| {{tt|SOS}}
| Start of String
| rowspan=3 | Takes an argument of a string of text, terminated by ST.<ref name="ECMA-48"/>{{Rp|5.6}} The uses for these string control sequences are defined by the application<ref name="ECMA-48"/>{{Rp|8.3.2,8.3.128}} or privacy discipline.<ref name="ECMA-48"/>{{Rp|8.3.94}}  These functions are rarely implemented and the arguments are ignored by xterm.<ref name="xtc"/> Some [[Kermit (protocol)|Kermit]] clients allow the server to automatically execute Kermit commands on the client by embedding them in APC sequences; this is a potential security risk if the server is untrusted.<ref name="CruzGianone1997">{{cite book|author1=Frank da Cruz|author2=Christine Gianone|title=Using C-Kermit|url=https://books.google.com/books?id=QuYQPc-c67MC&pg=PA278|year=1997|publisher=Digital Press|isbn=978-1-55558-164-0|page=278}}</ref>
|- id=PM
| {{tt|ESC ^}}
| {{tt|0x9E}}
| {{tt|PM}}
| Privacy Message
|- id=APC
| {{tt|ESC _}}
| {{tt|0x9F}}
| {{tt|APC}}
| {{nobr|Application Program Command}}
|}

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{{anchor|CBT|CCH|CHT|CTC|CVT}}
{{anchor|DA|DAQ|DCH|DL|DMI|EA|ECH|EF|EMI}}
{{anchor|EPA|ESA|FNT|GSM|GSS|HPA|HPR|HTJ|HTS|ICH}}
{{anchor|IL|IND|INT|JFY|MC|MW|NEL|NP|PLD}}
{{anchor|PLU|PP|PU1|PU2|QUAD|REP|RI|RIS|RM}}
{{anchor|SEM|SL|SM|SPA|SPI|SR|SSA}}
{{anchor|STS|TBC|TSS|VPA|VPR|VTS}}
{{anchor|SKR|KR}}