bash-hackers-wiki/original_source/commands/builtin/echo.txt

====== The echo builtin command ======

===== Synopsis =====
<code>
echo [-neE] [arg ...]
</code>

===== Description =====
''echo'' outputs it's args to stdout, separated by spaces, followed by a newline. The return status is always ''0''. If the [[commands:builtin:shopt|shopt]] option ''xpg_echo'' is set, Bash dynamically determines whether echo should expand escape characters (listed below) by default based on the current platform. ''echo'' doesn't interpret ''<nowiki>--</nowiki>'' as the end of options, and will simply print this string if given.

==== Options ====
^Option  ^Description  ^
| ''-n'' | The trailing newline is suppressed. |
| ''-e'' | Interpretation of the following backslash-escaped characters (below) is enabled. |
| ''-E'' | Disables the interpretation of these escape characters, even on systems where they are interpreted by default. |

==== Escape sequences ====
^Escape  ^Description  ^
| ''\a'' | alert (bell) |
| ''\b'' | backspace |
| ''\c'' | suppress further output |
| ''\e'' | |
| ''\E'' | an escape character |
| ''\f'' | form feed |
| ''\n'' | new line |
| ''\r'' | carriage return |
| ''\t'' | horizontal tab |
| ''\v'' | vertical tab |
| ''\\'' | backslash |
| ''\0nnn'' | the eight-bit character whose value is the octal value nnn (zero to three octal digits) |
| ''\xHH'' | the eight-bit character whose value is the hexadecimal value HH (one or two hex digits) |
| ''\uHHHH'' | the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value HHHH (one to four hex digits) |
| ''\UHHHHHHHH'' | the Unicode (ISO/IEC 10646) character whose value is the hexadecimal value HHHHHHHH (one to eight hex digits) |

===== Examples =====


===== Portability considerations =====
  * ''echo'' is a portability train wreck. No major shell follows POSIX completely, and any shell that attempts to do so should be considered horribly broken. [[http://pubs.opengroup.org/onlinepubs/9699919799/utilities/echo.html#tag_20_37|SUSv4]] specifies that ''echo'' **shall not** include any options. Further, it specifies that the behavior of ''-n'' as a first argument shall be determined by the implementation, unless XSI is followed, in which case ''-n'' is always treated as a string, and backslash escapes are interpreted by default. ''dash'' has the misfeature of following this and interpreting escapes by default, but includes a ''-n'' feature for suppressing newlines nevertheless.\\ \\ In practice, if you're able to assume a korn-like shell including bash, mksh, or zsh, ''echo'' when used in simple cases is generally reliable. For example, in the very common situation in which echo is supplied with a single argument and whose output is to have a newline appended, using ''echo'' is considered common practice. 

  * **Never use options to ''echo''! //Ever//!** Any time you feel tempted to use ''echo -e'', ''-n'', or any other special feature of echo, **use [[commands:builtin:printf|printf]] instead!** If portability is a requirement, you should consider using ''printf'' //exclusively// and just ignore that ''echo'' even exists. If you must use ''echo  -e'' and refuse to use ''printf'', it is usually acceptable to use ''echo $'...' ''if targeting only shells that support this special quoting style.

  * ''ksh93'' has a ''print'' command, which if coding specifically for ''ksh93'' should be preferred over ''echo''. [[commands:builtin:printf|printf]] still includes most of the functionality of both, and should usually be the most preferred option.

===== See also =====
  * [[commands:builtin:printf]]
  * http://cfajohnson.com/shell/cus-faq.html#Q0b
  * http://www.in-ulm.de/~mascheck/various/echo+printf/