Grep specific lines in a file

Question

my file looks like this

Tree:0,pos:0,len:2.29276,TMRCA:0.795328,ARG:,len:2.29276,TMRCA:0.795328
NEWICK_TREE:    [169]((2:0.147398,(6:0.136844,(((9:0.00903981,4:0.00903981):0.084126,5:0.0931658):0.0077254,(7:0.0053182,8:0.0053182):0.095573):0.0359525):0.0105546):0.647929,(0:0.199142,(1:0.0103058,3:0.0103058):0.188836):0.596186);
SITE:    0       0.0123617064        0.648849164    0010111111
iHistoryMax: 0
Tree:1,pos:0.0169589,len:2.28476,TMRCA:0.795328,ARG:,len:2.28476,TMRCA:0.795328
NEWICK_TREE:    [303]((2:0.147398,((6:0.00230499,1:0.00230499):0.134539,(((9:0.00903981,4:0.00903981):0.084126,5:0.0931658):0.0077254,(7:0.0053182,8:0.0053182):0.095573):0.0359525):0.0105546):0.647929,(0:0.199142,3:0.199142):0.596186);
iHistoryMax: 1
Tree:2,pos:0.0472255,len:2.77342,TMRCA:0.795328,ARG:,len:2.77342,TMRCA:0.795328
NEWICK_TREE:    [67](((6:0.00230499,1:0.00230499):0.134539,(((9:0.00903981,4:0.00903981):0.084126,5:0.0931658):0.0077254,(7:0.0053182,8:0.0053182):0.095573):0.0359525):0.658484,((0:0.199142,3:0.199142):0.436921,2:0.636062):0.159266);
iHistoryMax: 2
Tree:3,pos:0.0539094,len:2.96385,TMRCA:0.795328,ARG:,len:2.96385,TMRCA:0.795328
NEWICK_TREE:    [40](((6:0.00230499,1:0.00230499):0.134539,(((9:0.00903981,4:0.00903981):0.084126,5:0.0931658):0.0077254,(7:0.0053182,8:0.0053182):0.095573):0.0359525):0.658484,((0:0.389568,3:0.389568):0.246494,2:0.636062):0.159266);
iHistoryMax: 3

However, what I only need is the pos of each Tree (in the line Tree:1,pos) and the output should be only the number followed by pos in 1 column with 3 rows (or more). The position of the Tree line is not always in each 3 line as the part in between can change in length. This can be done in bash?

Answer 1

Use awk with a delimiter of : and , and then print the fields you want. For example, this will print the the Tree and pos numbers:

awk -F[:,] '/^Tree:/{print $2,$4}' file

Answer 2

using grep with -P

grep -Po "(?<=Tree.*pos:)[0-9.]+" file

0
0.0169589
0.0472255
0.0539094