[SOLVED] grep search between n-m

X.Cyclop · 10-05-2010, 03:41 PM

How can i use grep (or any other command) to check for lines that begin with N number.

E.g. I want to print out commands (from history), but only from the command number 50 until #200.

This one doesn't work:

Code:

history | grep "^[50-200]"

Should print out something like:

Code:

50 cd ~/Desktop
51 ls -lh
..........
199 gconftool-2 --set /apps/metacity/global_keybindings/panel_main_menu --type string "Super_L"
200 find . -name "x" -type f -size +100M

AlucardZero · 10-05-2010, 03:56 PM

grep doesn't work like that. grep is looking for patterns, not ranges of lines. You could construct a giant regex to only get those numbers, but that's a lot of work.

You can use head/tail or sed or awk to get only certain lines, for example

Code:

history | sed -n '50,200p'

Of course, the results may not actually start with 50-200, but they will be lines 50-200.

X.Cyclop · 10-05-2010, 04:05 PM

Great! thanks. I thought i wouldn't need sed, but now i see that i must learn it.

ghostdog74 · 10-05-2010, 07:17 PM

Quote:

Originally Posted by X.Cyclop

I thought i wouldn't need sed, but now i see that i must learn it.

its true, you don't need sed. all you need to learn is awk. It does the same function as sed and much more.

Code:

awk 'NR>50{print}NR>100{exit}' file

NR means "record number so far"

X.Cyclop · 10-06-2010, 04:28 AM

Maybe both? i see sed a bit easier and shorter.