Linux / Unix: sed Command Print Only Matching Lines

Posted on in Categories last updated October 19, 2012

I see many examples and man pages on how to do operations like search-and-replace using sed. But, I want to match a given string or a regular pattern expression and display on the screen. How do I print lines with matching pattern using sed command only under Unix like operating systems?

Bash: Get The Last Argument Passed to a Shell Script

Posted on in Categories last updated June 26, 2012

I‘m writing a bash wrapper script that will pass arguments to the command. I need to find out the last argument if I call the wrapper as follows:

./wrapper -a -b –longarg=foo thisfilename.txt
./wrapper -a -b thisfilename.txt
./wrapper -a –next=true thisfilename.txt

Where,
=> $@ is all of them.
=> $0 is script name.
=> $1 is first arg.

I want thisfilename.txt stored in a shell variable called $last. How do I find the last argument passed to a shell script written in bash or ksh under Unix like operating systems?