Add leading 0 in sed substitution

Question

I have input data:

foo 24
foobar 5 bar
bar foo 125

and I\'d like to have output:

foo 024
foobar 005 bar
bar foo 125
         


        

Answer 1

This might work for you (GNU sed):

echo '1.23 12,345 1 12 123 1234 1' | 
sed 's/\(^\|\s\)\([0-9]\(\s\|$\)\)/\100\2/g;s/\(^\|\s\)\([0-9][0-9]\(\s\|$\)\)/\10\2/g' 
1.23 12,345 001 012 123 1234 001

or perhaps a little easier on the eye:

sed -r 's/(^|\s)([0-9](\s|$))/\100\2/g;s/(^|\s)([0-9][0-9](\s|$))/\10\2/g'