How to extract numbers from a string?

Question

I have string contains a path

string=\"toto.titi.12.tata.2.abc.def\"

I want to extract only the numbers from this string.

To extrac

Answer 1

Fixing newline issue (for mac terminal):

cat temp.txt | tr '\n' ' ' | sed -e 's/[^0-9]/ /g' -e 's/^ *//g' -e 's/ *$//g' | tr -s ' ' | sed $'s/ /\\\n/g'

Answer 2

Parameter expansion would seem to be the order of the day.

$ string="toto.titi.12.tata.2.abc.def"
$ read num1 num2 <<<${string//[^0-9]/ }
$ echo "$num1 / $num2"
12 / 2

This of course depends on the format of $string. But at least for the example you've provided, it seems to work.

This may be superior to anubhava's awk solution which requires a subshell. I also like chepner's solution, but regular expressions are "heavier" than parameter expansion (though obviously way more precise). (Note that in the expression above, [^0-9] may look like a regex atom, but it is not.)

You can read about this form or Parameter Expansion in the bash man page. Note that ${string//this/that} (as well as the <<<) is a bashism, and is not compatible with traditional Bourne or posix shells.

Answer 3

Use regular expression matching:

string="toto.titi.12.tata.2.abc.def"
[[ $string =~ toto\.titi\.([0-9]+)\.tata\.([0-9]+)\. ]]
# BASH_REMATCH[0] would be "toto.titi.12.tata.2.", the entire match
# Successive elements of the array correspond to the parenthesized
# subexpressions, in left-to-right order. (If there are nested parentheses,
# they are numbered in depth-first order.)
first_number=${BASH_REMATCH[1]}
second_number=${BASH_REMATCH[2]}

Answer 4

Using awk:

arr=( $(echo $string | awk -F "." '{print $3, $5}') )
num1=${arr[0]}
num2=${arr[1]}