sed command
 

I am using this command:
sed '2i\add it where ever it is supposed to be' auto.test

to insert the line at 2nd line(position) in auto.test

although I can see the correct results on screen but could not see
the results if I open auto.test using

vi auto.test

Re: sed command
 

Resloved it!!!!!!!!!!THANKS

Sed's output is to stdout, you need to redirect the output to a file (do not use the same filename!!!).

$ sed '2i\add' auto.test > auto.test.out
$ cat auto.test.out
If file is ok:
$ mv auto.test.out auto.test

Do not use the same name for the infile and outfile (sed 4.x has a parameter for this).

Hope this helps.

-..........................>>>>>>>>>>>>>>>

Thank you for your reply.....now this is a inserting operation if we hard code the
string in sed statement but what if I would like to change string dynamically
depending on users request...

I hope I am clear here....otherwise I will just repeat myself..

All I am trying is ...how can I insert a string(that can be different each time
user types in) dynamically into a file....I realized that using sed command that
string has to be hard coded...so I am looking to insert dynamically....

You need to use the appropriate quotes and escape the $:

$ THIS_LINE="Whatever you want"
$ echo $THIS_LINE
Whatever you want
$ sed "2i\\$THIS_LINE" auto.test
line 01
Whatever you want
line 02
line 03
line 04
line 05

Hope this is what you wanted to know.

Thank you very much.. It worked but..
I tired following for dynamically substituting text:
sed "s\\replace\$THIS_LINE" auto.test >auto1.test

but it is not working?
How can I attain dymanic substitution?

sed "s\\replace\`echo $THIS_LINE`" auto.test >auto1.test


Cheers,
Tink

----------->>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
Thank you for your response..

I tired the command:

sed "s\\addation\`echo $command`" auto3.test >auto4.test

and got this error message:
./auto2.test: line 5: unexpected EOF while looking for matching ``'
./auto2.test: line 7: syntax error: unexpected end of file

Sorry, I just copied your faulty line and put my
stuff into it .... thry this one

Cheers,
Tink

Here is something which may work for you...
The extra quotes are needed around the $info so sed will process a line with spaces in it.
The $num should not have that problem as it is an actual line number.