Linux / Unix: sed Command Print Only Matching Lines

in Categories UNIX 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 History: Correct / Repeat The Last Command With a Substitution

in Categories BASH Shell, Linux, UNIX last updated February 23, 2016

I often type the wrong command as follows under Linux bash shell:

rsync -av dir1


cp -av file1*.txt file2*.txt /path/to/dest

I need to correct those command as follows:

rsync -av dir5
cp -av delta1*.txt delta2*.txt /path/to/dest

How do I replace dir1 with dir5 or file with delta and repeat the last command under bash shell?

Bash: Get The Last Argument Passed to a Shell Script

in Categories BASH Shell 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

=> $@ 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?

Firefox Disable / Hide New Tab Page

in Categories Mozilla Software last updated June 19, 2012

I‘ve upgraded to Firefox v13. However, I don’t like the new tab page. I’m concerned about my privacy. How do disable or hide new tab page while using Firefox browser version 13? How do you get rid of the “new tab” page that shows recently visited pages?