PWB1/usr/man/man1/pump.1

.th PUMP I 5/31/77
.sh NAME
pump \*- Shell data transfer command
.sh SYNOPSIS
.bd pump
[
.bd \*-\c
[\c
subchar] ]
[
.bd +
]
[ eofstr ]
.sh DESCRIPTION
.it Pump
is a filter that copies its
standard input to standard output with possible substitution of Shell
arguments and variables.
It reads its input to end-of-file, or until it finds
.it eofstr
alone on a line.
If not specified,
.it eofstr
is assumed to be `!'.
Normally, Shell variable and argument values are substituted in the
data stream, using `$' as the character to indicate their presence.
The argument `\*-' alone suppresses all substitution,
.it `\*-subchar'
causes
.it subchar
to be used as the indicator character for substitution in place of `$'.
Escaping is handled as in double quoted(") strings: the indicator character may
be hidden by preceding it with a `\\'.
Otherwise, `\\' and other characters are transmitted unchanged.
The `+' flag causes all leading tab characters in the input to
be thrown away, in order to permit readable indentation
of text and
.it eofstr.
.it Pump
may be used interactively and in pipelines.
A common use is to get variable values into editor scripts.
If $a, $b, and $c have the values A, B, and C respectively,
the two sequences below are equivalent:
.s3
.tr ||
.nf
.if n .ta 30
.if t .ta 2.5i
pump \*-~ \*v ed file	ed file
1,$s/~a$/~b/	1,$s/A$/B/
?~c?	?C?
!	q
.fi
.s3
The sequence above will work at the terminal as well as in Shell procedures.
.it Pump
is an efficient and convenient replacement for multiple uses of
.it "echo(I);"
e.g., the following are equivalent:
.s3
.nf
.if n .ta 30
.if t .ta 2.5i
pump >file	echo "$1" >file
$1	echo "$2" >>file
$2
!
.fi
.s3
.it Pump
is actually implemented inside the Shell, although it executes as
a separate process.
.sh "SEE ALSO"
echo(I), sh(I)
.sh BUGS
The size of
.it eofstr
is limited to 95 bytes,
and it may not begin with `+'.