awk: regular expressions and group submatch capture

b=`ssh root@registration.authinfra.net 'rpm -qg pi'`

echo $b | awk 'match($0, "pi-multihome-[[:digit:]].[[:digit:]]-([[:digit:]]*)", a) {print a[1]}'

OUTPUT: 125324

vim: mapping the F2 key to a sequence of commands

Macros are a great way to automate tasks in vim. You can record a sequence of keystrokes, assign them to a register, and then playback the macro saved in that register any number of times.

However, sometimes you come across a macro that is so useful that you use it frequently. Perhaps you use it across several vim sessions. You wish you could create a keyboard shortcut for this macro, and then save it in your ~/.vimrc file for anytime usage.

This is how you can do that, using vim’s map command:

map <F2> 0i\<Esc>A\n\<Esc>j

This mapping will bind the F2 key to perform this sequence of operations:

number	operation	vim command
1	go to the hard BOL (beginning of line)	0
2	insert the '\' character	i\
3	go back to command mode	<Esc>
4	append \n\ to the end of the line	A\n\
5	go back to command mode	<Esc>
6	go down one line (so that you can just press F2 again on the next line, to continue)	j

gdb: set a conditional breakpoint

(gdb) break LinkedList<int>::remove
Breakpoint 1 at 0x29fa0: file main.cc, line 52.
(gdb)
(gdb) condition 1 item_to_remove==1

Another way to accomplish this:

break LinkedList<int>::remove if (item_to_remove==1)

source:
http://www.cs.cmu.edu/~gilpin/tutorial/#3.4