Echo writes its arguments separated by blanks and terminated by a newline on the standard output. Options to filter and redirect the output are as follows:

-2 generate rhyming couplets from keywords

-3 generate Haiku verse from keywords

-5 generate limerick from keywords

-a convert ASCII to ASCII

-A disambiguate sentence structure

-b generate bureaucratese equivalent (see -x)

-B issue equivalent C code with bugs fixed

-c simplify/calculate arithmetic expression(s)

-C remove copyright notice(s)

-d define new echo switch map

-D delete all ownership information from system files

-e evaluate lisp expression(s)

-E convert ASCII to Navajo

-f read input from file

-F transliterate to french

-g generate pseudo-revolutionary marxist catch-phrases

-G prepend GNU manifesto

-h halt system (reboot suppressed on Suns, Apollos, and VAXen, not supported on NOS-2)

-i emulate IBM OS/VU (recursive universes not supported)

-I emulate IBM VTOS 3.7.6 (chronosynclastic infundibula supported with restrictions documented in IBM VTOS

-J generate junk mail

-j justify text (see -b option)

-k output “echo” software tools

-K delete privileged accounts

-l generate legalese equivalent

-L load echo modules

-M generate mail

-N send output to all reachable networks (usable with -J, -K, -h options)

-n do not add newline to the output

-o generate obscene text

-O clean up dirty language

-p decrypt and print /etc/passwd

-P port echo to all reachable networks

-P1 oolcay itay

-q query standard input for arguments

-r read alternate “.echo” file on start up

-R change root password to “RMS”

-s suspend operating system during output (Sun and VAX BSD 4.2 only)

-S translate to Swahili

-T emulate TCP/IP handler

-t issue troff output

-u issue unix philosophy essay

-v generate reverberating echo

-V print debugging information

-x decrypt DES format messages (NSA secret algorithm CX 3.8, not distributed outside continental US)

Echo is useful for producing diagnostics in shell programs and for writing constant data on pipes. To send diagnostics to the standard error file, do ‘echo … 1>2’.