Control-\

In computing, control-\ is a control character in ASCII code and the Basic Latin code block of Unicode, also known as the file separator or field separator (FS) character. It is generated by pressing the key while holding down the  key on a computer keyboard, and has the decimal value 28 (or 1c in hexadecimal). It is the highest-level of the four separators in the ASCII C0 and C1 control codes; the others are control-] (group separator), control-^ (record separator), and control-_ (unit separator). It was one of eight codes reserved as separators in the 1963 version of the ASCII standard; these were reduced to four separators in a 1965 revision of the standard.

In its use as a file separator, this character can be used to subdivide textual data into records or other semantic units; for instance, it has this role in the ANSI/NIST-ITL Standard Data Format for the Interchange of Fingerprint, Facial & Other Biometric Information.

Under most UNIX-based operating systems control-\ is used to terminate a running process from a command shell and have it produce a memory core dump by sending it a SIGQUIT signal. Other similar ways of terminating or interrupting a shell process include Control-C, Control-Z, and the kill command.

As a character that can be easily typed on most keyboards, but with no standardized meaning, control-\ is often used as a keyboard shortcut in different graphical user interfaces, with various unrelated effects. For instance, some versions of Windows File Manager use it to de-select all selected files. In Adobe InDesign, it has been used to mark a point in a line of text as the starting position of a hanging indent.