The vertical bar, |, is a glyph with various uses in mathematics, computing, and typography. It has many names, often related to particular meanings: Sheffer stroke, pipe, bar, or, vbar, and others.
US International keyboard showing broken bar on the keycap, even though pressing ⇧ Shift+\ produces the solid vertical bar.
A command-line interface (CLI) is a means of interacting with a computer program by inputting lines of text called command-lines. Command-line interfaces emerged in the mid-1960s, on computer terminals, as an interactive and more user-friendly alternative to the non-interactive interface available with punched cards.
The end of the HELP command output from RT-11SJ displayed on a VT100
A Teletype Model 33 ASR teleprinter keyboard with punched tape reader and punch
DEC VT52 terminal