put rows of numbers into a column with shell script

Question

I have a file with many lines, like

1 jfkdajfd   1 2 3 5
2 fkldfjld   
3 fdkfloaf   9 10
4 fldfldkf 
5 fdskf;ak   12 1 4

I want to get all the numbers and put them in a column in a file, like

 1
 2
 3
 5
 9
 10
 12
 1
 4

how can I achieve this? thanks

Answer 1

Try

awk '{ for (i = 1; i <= NF; i++) if ($i + 0 == $i) print $i }' < input > output

I use x + 0 == x as the test to see if x is a valid awk number, then print the original string. It's up to you to decide if you want awk numbers (this includes floating point, negative numbers, and on many implementations, hexadecimal numbers as well), or something different.

Answer 2

How about

tr -cs 0-9 '[\n*]' < input | grep . > output