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echo began within Multics.After it was programmed in C by Doug McIlroy as a "finger exercise" and proved to be useful, it became part of Version 2 Unix. echo -n in Version 7 replaced prompt, (which behaved like echo but without terminating its output with a line delimiter).
(Hence the name, ECHO) Usually, this means directly to the screen, but the output of echo can be redirected, like any other command, to files or devices. Often used in batch files to print text out to the user. Another important use of the echo command is to toggle echoing of commands on and off in batch files.
The standard utility program that alters this flag programmatically is the stty command, using which the flag may be altered from shell scripts or an interactive shell. [25] The command to turn local echo (by the host system) on is stty echo and the command to turn it off is stty-echo. [26] [fn 2]
The Echo Protocol is a service in the Internet Protocol Suite defined in 1983 in RFC 862 by Jon Postel. It was originally proposed as a way to test and measure an IP network. A host may connect to a server that supports the Echo Protocol using the Transmission Control Protocol (TCP) or the User Datagram Protocol (UDP) on the well-known port ...
The Echo Connect is a small adapter that plugs into any Echo and a home phone line, allowing the Echo to make voice calls through a home phone number. [ 99 ] In September 2018, Amazon announced the Echo Sub , a subwoofer that connects to other Echo speakers, and the Echo Wall Clock , which can display how much time is remaining on timers set ...
The Hayes command set (also known as the AT command set) is a specific command language originally developed by Dale Heatherington and Dennis Hayes [1] [2] for the Hayes Smartmodem in 1981. The command set consists of a series of short text strings which can be combined to produce commands for operations such as dialing, hanging up, and ...
The traceroute command can be implemented by transmitting IP datagrams with specially set IP TTL header fields, and looking for ICMP time exceeded in transit and destination unreachable messages generated in response. The related ping utility is implemented using the ICMP echo request and echo reply messages.
On POSIX systems, one may also use: printf '\a' and in the Bash shell, one may use ANSI-C quoting: [5] echo $'\a' An alternative is to use the tput command, which as a part of the ncurses library is available on most Unix/Linux operating systems: tput bel A program can get the same result by printing the BEL character to a terminal.