topic Re: add new string using sed in Operating System - HP-UX

add new string using sed

Sergejs Svitnevs — Wed, 28 Jan 2004 10:59:23 GMT

Hi all.

I have a shell variable $x.

# echo $x
HELLO UNIX

I also have an ASCII file hello.txt.

#cat hello.txt
HELLO LINUX
HELLO WINDOWS

How can I add a value of the shell variable $x to the end of my file using sed?

"cat $x >> hello.txt" is not useful to me.

Your help with SED statement is appreciated.

Thanks,
Sergejs

Re: add new string using sed

A. Clay Stephenson — Wed, 28 Jan 2004 11:03:42 GMT

This is pointless to do with sed -- although it can be done. You should realize that sed can never edit a file directly; it creates a new file. Often a temp file is created based upon the input file and then the temp file is mv'ed to the input file.

This will worl just fine and will do the job with the file in place:
echo "${x}" >> hello.txt

Re: add new string using sed

Kent Ostby — Wed, 28 Jan 2004 12:31:06 GMT

Sergejs --

Perhaps you could tell us more about the application that you want to use this in or explain why you want to use sed to do this operation ?

Best regards,

Kent M. Ostby

Re: add new string using sed

Sridhar Bhaskarla — Wed, 28 Jan 2004 12:39:06 GMT

Hi Segejs,

You will need to use 'echo' instead of "cat" to print $x into hello.txt.

echo "$x" >> hello.txt

If you insist of sed, below is the way

sed 's/$/'"$x"'/' hello.txt > 1
mv 1 hello.txt

-Sri

Re: add new string using sed

Aupee Jean-Francois — Thu, 29 Jan 2004 05:30:25 GMT

Hi

It's better to do that with ex :

#ex -s FILE << EOF
> /^TOTO/
> s/TOTO/TOTO2/
> w
> EOF

TOTO=variable
TOTO2=new variable

Best regards

Re: add new string using sed

Karthik S S — Thu, 29 Jan 2004 05:52:18 GMT

Since you are insisting on using sed :-)),

#echo >> hello.txt

#sed /^$/s/^$/"$x"/g hello.txt
HELLO LINUX
HELLO WINDOWS
HELLO UNIX

However here I assume that there are no blank lines else where in this file than the end of file.

-Karthik S S

Re: add new string using sed

Karthik S S — Thu, 29 Jan 2004 06:27:20 GMT

Another method,

create a file (sedfile in this example) with the following two lines,

$a\
Whatever string you want

sed -f sedfile hello.txt

cat hello.txt
HELLO LINUX
HELLO WINDOWS
Whatever string you want

However sed can not substitute the variables with in the input file.

-Karthik S S