Shell Programming and Scripting

Hi

I want to grep for a line and copy and paste that line.

for Example

---- file abc.txt ----
host=atlx1 sid=atld1 mail=abc@abc.com
host=atlx2 sid=atld2 mail=xyz@abc.com
host=atlx3 sid=atld3 mail=def@abc.com
host=atlx4 sid=atld4 mail=mno@abc.com
--- end of file abc.txt ----

Now I want to grep line with host=atlx3 and sid=atld3 and copy and paste the line and ALSO put "#" in front of one of the line. The following is the output I would like to see...

---- file output.txt ----
host=atlx1 sid=atld1 mail=abc@abc.com
host=atlx2 sid=atld2 mail=xyz@abc.com
#host=atlx3 sid=atld3 mail=def@abc.com
host=atlx3 sid=atld3 mail=def@abc.com
host=atlx4 sid=atld4 mail=mno@abc.com
--- end of file output.txt ----

How can I do this in shell script.

Thanks in advance for your help.

RK

Assuming this precise sequence of host and sid is the deciding criterion, maybe something like

Code:

sed '/host=atlx3 sid=atld3/{;h;s/^/#/p;x;}' abc.txt

This takes a matching line and remembers it in the hold space (h); then substitutes a hash mark at beginning of line and prints the result; then swaps back the hold space (x) which will be printed as any other line a second time.

Thank you so much for your help.

Another question :

How can I also replace "mail=def@abc.com" with "mail=DISABLE" in the line which is NOT commented out ('#').

Thanks Again

Code:

sed '/host=atlx3 sid=atld3/{;h;s/^/#/p;x;s/mail=.*/mail=DISABLE/;}' abc.txt

Thank You, works perfectly....

Sincere apologies for asking another question but I am very new to scripting and need some HELP.

Question:

How to reverse it.. means find the line with host=atlx3 sid=atld3 and mail=DISABLE and then delete this line and at the same time un-comment ('#') the line above it..

--- INPUT.TXT ------
host=atlx1 sid=atld1 mail=abc@abc.com
host=atlx2 sid=atld2 mail=xyz@abc.com
#host=atlx3 sid=atld3 mail=def@abc.com
host=atlx3 sid=atld3 mail=DISABLE
host=atlx4 sid=atld4 mail=mno@abc.com
-------------------------

---- OUTPUT.txt -----
host=atlx1 sid=atld1 mail=abc@abc.com
host=atlx2 sid=atld2 mail=xyz@abc.com
host=atlx3 sid=atld3 mail=def@abc.com
host=atlx4 sid=atld4 mail=mno@abc.com
--------------------

Assuming the # at beginning of line is always a sign that this should be done,

Code:

sed -e '/^#/{;s///p;N;d;}' INPUT.TXT

I wanted to look for host and sid and then delete a line with mail=DISABLE and un-comment the line above it. The reason... in actual there may be many lines in the file with '#' at the beginning but wanted to delete as per the above criteria and then un-comment the line above it.

thanks again