The echo command writes its arguments separated by blanks
and terminated by a new line on the standard output. The
-n option prints a line without the newline; this is the
same as using the ``\c'' escape sequence if it is placed at
the end of the list of arguments.
However, POSIX.2 and the X/Open CAE Specification, Commands and Utilities, Issue 4, 1992 do not support the
-n option, so if you are using /bin/posix/echo
rather than /bin/echo, the newline will always be printed.
In this case, it may be suppressed using the
printf(C)
command.
echo also understands C-like escape conventions; beware of
conflicts with the shell's use of ``\'':
\a
alert character (for example, ASCII BEL)
\b
backspace
\c
ignore all subsequent arguments, and do not output a newline
\f
form-feed
\n
new line
\r
carriage return
\t
tab
\v
vertical tab
\\
backslash
\0n
The 8-bit character whose ASCII code is a
0, 1, 2 or 3-digit octal number n. To prevent the argument
being quoted literally, it must be escaped from the shell. For
example:
echo '\065'
echoes the number ``5''
echo \\0101
echoes the letter ``A''
For the octal equivalents of each character, see
ascii(M).
The echo command is useful for producing diagnostics in
command files and for sending known data into a pipe.
A version of this command is built into
ksh(C)
and
sh(C).
Examples
When representing an 8-bit character by using the escape convention
\0n, the octal number n must
always be preceded by the digit zero (0).
For example, typing: echo "WARNING:\07" will
print the phrase ``WARNING:'' and sound the ``bell'' on
your terminal. The use of single (or double) quotes (or two
backslashes) is required to protect the ``\'' that precedes
the ``07''.
Limitations
The version of echo built into
csh(C)
only supports the escape sequences ``\c'' and ``\n''.