Shell Programming and Scripting

Is it possible to do search and replace in unix
Like :

s/some date/current date/g

some date and current date both are in same format (dd/mm/yyyy hh:mm:ss)


My requirement is :
I am having a variable which holds last run date. After running my shell script I want to do update this variable with the current date.

Code:

#!/bin/sh
eval "sed -n 's/[0-9]\{2\}\/[0-9]\{2\}\/[0-9]\{4\} [0-9]\{2\}:[0-9]\{2\}:[0-9]\{2\}/`date '+%m\/%d\/%Y %H:%M:%S'`/gp' inputfile > outputfile"

Thanks for the reply.

Also please if you suggest that :

In my shell script can i declare a variable (last_run_time) in the begining, Use this variable thru the code and before exiting the shell script update this variable with the code you supplied..



.... shell script start .....
last_run_time=16/03/2005 10:10:10
..
spool test
select * from table1 where creattion_date > $last_run_time;
spool off
..

****
Here i wanted to update the last_run_time variable (declared above) with the current date, so that the next time i run the script i shd get the records which are inserted after i last ran the query
****
.... shell script end .....




Regards