V10/man/man1/echo.1

.TH ECHO 1 
.CT 1 shell
.SH NAME
echo, printf \- print arguments
.SH SYNOPSIS
.B echo
[
.B -n
]
[
.B -e
]
[
.I arg ...
]
.PP
.B printf
[
.I format
[
.I arg...
]
]
.SH DESCRIPTION
.I Echo
writes its arguments separated by blanks and terminated by
a newline on the standard output.
Option
.B -n
suppresses the newline.
.PP
Option 
.B -e
enables the interpretation of C-style escape codes,
.LR \eb ,
.LR \ef ,
.LR \en ,
.LR \er ,
.LR \et ,
.LR \e\e ,
.L and 
.BI \e ddd,
where
.I d
is an octal digit,
plus the special code
.LR \ec ,
which terminates the output.
.PP
.I Echo
is useful for producing diagnostics in
shell programs and for writing constant data on pipes.
.PP
.I Printf
behaves like the library function of the same name; each
.I arg
is printed on the standard output according to the corresponding
\&%-introduced specification in the
.I format
string.  The standard C escape sequences
.BR \en ,
.BR \er ,
.BR \et ,
.BR \eb ,
and
.BI \e digits
are recognized in
.IR format .
The
.I arg
will be treated as a string if the corresponding format is
.BR s ;
otherwise it is evaluated as a C constant, with the following extensions:
.IP
A leading plus or minus is allowed.
.IP
If the leading character is a single or double quote, the value is the
.SM ASCII
code of the next character.
.IP
Otherwise, if the leading character is not a digit, the value is its
.SM ASCII
code.
.PP
The format string is reused as often as necessary to satisfy the
.IR arg "'s."
Any extra format specifications are evaluated with zero or the null string.
.SH EXAMPLES
.TP
.L
echo "can't open file" $1 1>&2
Send a message to the standard error file.
.SH SEE ALSO
.IR printf (3)
.SH BUGS
.I Printf
has no diagnostics for illegal syntax.