Editing ASCII (section)

====End of file/stream====
The PDP-6 monitor,<ref name="pdp-6-monitor-manual"/> and its PDP-10 successor TOPS-10,<ref name="pdp-10-monitor-manual"/> used control-Z (SUB) as an end-of-file indication for input from a terminal.  Some operating systems such as CP/M tracked file length only in units of disk blocks, and used control-Z to mark the end of the actual text in the file.<ref>{{cite book |url=http://www.bitsavers.org/pdf/digitalResearch/cpm/1.4/CPM_1.4_Interface_Guide_1978.pdf |title=CP/M 1.4 Interface Guide |date=1978 |page=10 |publisher=[[Digital Research]] |access-date=October 7, 2017 |archive-url=https://web.archive.org/web/20190529055800/http://bitsavers.org/pdf/digitalResearch/cpm/1.4/CPM_1.4_Interface_Guide_1978.pdf |archive-date=May 29, 2019 |url-status=live }}</ref> For these reasons, EOF, or [[end-of-file]], was used colloquially and conventionally as a [[three-letter acronym]] for control-Z instead of SUBstitute.  The end-of-text character ([[End-of-text character|ETX]]), also known as [[control-C]], was inappropriate for a variety of reasons, while using control-Z as the control character to end a file is analogous to the letter Z's position at the end of the alphabet, and serves as a very convenient [[Mnemonic device|mnemonic aid]]. A historically common and still prevalent convention uses the ETX character convention to interrupt and halt a program via an input data stream, usually from a keyboard.

The Unix terminal driver uses the end-of-transmission character ([[End-of-Transmission character|EOT]]), also known as control-D, to indicate the end of a data stream.

In the [[C programming language]], and in Unix conventions, the [[null character]] is used to terminate text [[string (computer science)|strings]]; such [[null-terminated string]]s can be known in abbreviation as ASCIZ or ASCIIZ, where here Z stands for "zero".