Display message on screen.
Syntax
echo [options]... [String]...
Options
-n
Do not output the trailing newline.
-E
Disable the interpretation of the following backslash-escaped characters.
-e
Enable interpretation of the following backslash-escaped characters in each String:
\a Alert (bell)
\b Backspace
\c Suppress trailing newline
\e Escape
\f Form feed
\n New line
\r Carriage return
\t Horizontal tab
\v Vertical tab
\\ Backslash
\0NNN The character whose ASCII code is NNN (octal); NNN can be 0 to 3 octal digits.
The echo utility exits 0 on success, and >0 if an error occurs.
This is a BASH shell builtin, to display your local syntax from the bash prompt type: help echo
There is also an echo utility (man echo) , but the shell built-in version will generally take precedence.
echo "Hello World"
DEMO=Testing123
echo "$DEMO"
# Testing123
echo "with quotes we can echo
several lines at a time"
To produce a default beep:
$ echo '^G^G^G^G'
Enter the ^G characters (which represent ASCII 7, the BEL character) by typing Ctrl-v Ctrl-g
Echo can also display in color using Escape sequences for foreground (30..37) and background (40..47) colours.
Terminal.app preferences give much finer control over colors (background + selected text).
$ COL_BLUE="\x1b[34;01m"
$ COL_RESET="\x1b[39;49;00m"
$ echo -e $COL_BLUE"Important Message: "$COL_RESET"This is a message"
A shell script to display all the color combinations:
#!/bin/bash
#
echo ---Bg---40---41---42---43---44---45---46---47
for i in {30..37} # foreground
do
echo -n -e fg$i-
for j in {40..47} # background
do
echo -n -e '\E['$i';'$j'm SS64'
tput sgr0 # Reset text attributes to normal without clear
done
echo # newline
done
echo -- Clear BG --
for n in {30..37} # foreground
do
echo -e fg$n '\E['$n';'01'm SS64'
tput sgr0 # Reset text attributes to normal without clear
done
QED - Quod erat demonstrandum. [Thus it is proven.]
lpr - Print files.
printf - Format and print data.
say - Convert text to audible speech.
wall - Write a message to users.