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From: jgy@hropus.UUCP (John Young)
Newsgroups: comp.unix.wizards
Subject: Re: embedded newlines in shell variable?
Message-ID: <1243@hropus.UUCP>
Date: Wed, 12-Aug-87 16:44:20 EDT
Article-I.D.: hropus.1243
Posted: Wed Aug 12 16:44:20 1987
Date-Received: Sat, 15-Aug-87 09:42:01 EDT
References: <228@cjsa.UUCP>
Organization: Bell Labs, Holmdel, NJ
Lines: 58
Keywords: sed sh shell

> I have been attempting to construct a 'sed' command line script and load it
> into a shell variable (called ACTION) for later use within a bourne shell
> script.  All goes well until I need sed to append new text to the end of the
> input data.  To work, sed's append command ( a\ ) requires newlines to be
> embedded as follows:
> 			'$a\
> 			NEW LINE OF MATERIAL'
> 
> 
> What follows is an example of what I am attempting to achieve:
> 
> Match last line ------++-----Append text
> 		      ||
> 		      vv
> 	ACTION=" -e '\$a\\nNEW LINE OF MATERIAL'"
> 	...
> 	sed  ${ACTION} $1
> 
> 
> My experience has been that using '\n' in the assignment get the newline
> into the variable so that  echo $ACTION  prints correctly, but sed will
> not interpret the '\n' sequence properly.
> 
> On the other hand, attempting to embed actual newlines (^J) within the
> assignment (ie. ACTION="-e '\$a\^JNEW LINE OF MATERIAL'") does not work
> since the shell substitutes the ^J with a single space.
> 
> I have tried to escape every character in sight and even attempted an
> eval on $ACTION under various modes of construction, without success.
> 
> I'm guessing that there is a simple (and obvious) trick for doing what I
> want.  Any pointers would be greatly appreciated.
> 
> Thanks in advance.
> ----
> Jeffery Small          (203) 776-2000     UUCP:   ihnp4!---\
> C. Jeffery Small and Associates	                            hsi!cjsa!jeff
> 123 York Street, New Haven, CT  06511          hao!noao!---/
> 

Try this:

# action="\$a\\
hello\\
world"
# date | sed -e "$action"

You need to get the a single backslash thru to sed prior to each
end of line.

I hope this isn't all you want, because if so:
# echo "NEW LINE OF MATERIAL" >> file
or
# {
cat file
echo "NEW LINE OF MATERIAL"
}
would be much edididor