[ILUG] substituting shell variables with sed

[Conor Daly]

It's probably a FAQ but how do I substitues a shell variable with sed?  I
have the following:

PATH_MPAGE=`which mpage`

and then later:

cat ./dprint | sed -e 's at mpage@\$PATH_MPAGE@' > dprint.out

but grep -i mpage dprint.out gives the following:

$PATH_MPAGE -$PAGES_UP -a -X -m10l0t50b40r -r -j 1%2 -P$PRINTER $FILE
$PATH_MPAGE -$PAGES_UP -a -X -m20l-10t50b40r -j 2%2 -P$PRINTER $FILE

where I want 

/usr/bin/mpage -$PAGES_UP -a -X -m10l0t50b40r -r -j 1%2 -P$PRINTER $FILE
/usr/bin/mpage -$PAGES_UP -a -X -m20l-10t50b40r -j 2%2 -P$PRINTER $FILE

or whatever the output of `which mpage` is.  I tried stuff like 

sed -e 's at mpage@\${PATH_MPAGE}@'  and

sed -e 's at mpage@"$PATH_MPAGE"@'

but keep getting "$PATH_MPAGE" in the output.  Any thoughts?

TIA

-
Conor Daly <conor.daly at oceanfree.net>

Domestic Sysadmin :-)
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