Cfrtjryk

So I have a list of random websites of the following kind:

   rapido21655bonk.a.sweetpotato.net

   rapido26230bonk.a.sourpotato.net

   rapido29926bonk.b.sourpotato.net

   rapido29926bonk.b.sweetpotato.net

   rapido30179bonk.a.sweetpotato.net

   rapido30648bonk.b.sourpotato.net

   rapido30761bonk.c.sweetpotato.net

Now I need a sed string to only leave the number, and take everything else out. What I did was:
sed s/rapido// to get rid of the first part of it, but for the second part, I could use sed twice to get rid of them both, but I want to know if I can use some kind of or logic to remove both in one sed. I know I can use sed to match a or b or c using [abc] but I want something like that for whole words. So what I did after this was:

sed s/rapido//|sed s/bonk.[abc].sweetpotato.net// and then I would put another one with just sourpotato.net, but I can't seem to do the following:

sed s/rapido//|sed s/bonk.[abc].(sweet|sour)potato.net//
This doesn't work. It gives me this:
-bash: syntax error near unexpected token('`

Only replacing the number doesn't not work, because sometimes I might get stuff like rapido22452boonkers.red which I would want to still have there. I would want to ONLY remove the 2 alternatives sweetpotato.net OR sourpotato.net.

[111@111 ~]$ sed s/rapido// sedster|sed 's/bonk.[abc].(sweetpotato|sourpotato).net//'

   21655bonk.a.sweetpotato.net

   26230bonk.a.sourpotato.net

   29926bonk.b.sourpotato.net

   29926bonk.b.sweetpotato.net

   30179bonk.a.sweetpotato.net

   30648bonk.b.sourpotato.net

   30761bonk.c.sweetpotato.net

With

sed -r 's/([^0-9]*)([0-9]*)([^0-9]*)/2/g'

you can keep only the number in the middle. This only works with extended regular expressions, so you need the -r option to sed.

Actually, it suffices to use

sed -r 's/([^0-9]*)([0-9]*)(.*)/2/g'

This uses the function of referencing parts of the expression with 1, 2, ... You then have to use parentheses (...) around the part of your expression you want to reference. In the above code, the second part ([0-9]*) will match the number in the middle, and you can refer to this by 2.

Edit: As terdon pointed out, we don't need to capture the initial part since we don't use it again. So

sed -n -r 's/[^0-9]*([0-9]+).*/1/p'

is enough.

To summarize, the command above keeps only the first number in your input line.

If you just want to extract the numbers, you can do this with GNU grep:

$ grep -oP 'd+' file

21655

26230

29926

29926

30179

30648

30761

Or, portably with perl:

$ perl -pe 's/[^dn]+//g' file

21655

26230

29926

29926

30179

30648

30761

Or sed:

$ sed -nE 's/[^0-9]+//gp' file

21655

26230

29926

29926

30179

30648

30761

If you need something more specific to your input data, you can try:

$ sed -nE 's/.*rapido([0-9]+)bonk...(sweet|sour)potato.net.*/1/p' file

21655

26230

29926

29926

30179

30648

30761

Your attempt

sed s/rapido// | sed s/bonk.[abc](sweet|sour)potato.net//

was actually pretty close, but you made two mistakes. The first is that you didn't put the command inside quotes, so bash interpreted the special characters "(" and "|". (The fact that you got a bash error message should have tipped you off to this).

The second mistake is more subtle. Sed and grep use basic regular expressions, in which only a few characters ( . * ^ $ [ ] ) have special meaning. If you want to use extended regex operators ( | () {} ), you need to precede them with a backslash. So here's what your command should have looked like:

sed < t 's/rapido//' | sed 's/bonk.[abc].(sweet|sour)potato.net//'

and since sed can handle multiple commands in one run, you can simplify this to

sed < t 's/rapido//; s/bonk.[abc].(sweet|sour)potato.net//'