Shell Programming and Scripting

Let's say I have an input file looking like:

Code:

ID1
1    5
6    8
ID2
1    4
5    7

I'm trying to formulate a loop that can combine these actions:
- If the line begins with a letter: replace the '\ n' after a field containing characters with a '\ t' (sed 's / \ n / \ t / g' )
- If the line begins with a number: replace every '\ t' and '\ n' with a comma (sed 's / \ t /, / g; s / \ n /, / g ') EXCEPT if the next line begins with a letter (sed 's / \ t /, / g')


Expected output:

Code:

ID1     1, 5, 6, 8
ID2     1, 4, 5, 7

This is what I tried so far (but I have no idea of how I could format it properly) :

Code:

sed '$1 ~ /^[A-Z]|^[1-9]/ {if ~ /^[A-Z] 's/\n/\t/g'; else if ~ /^[1-9] 's/\n/,/g'}'

Any help would be appreciated Thanks in advance

sed does not have if...else constructs. You could use awk for this. With sed and exactly the sample structure that you supplied, this might work:

Code:

sed '/^[[:alpha:]]/ {N;N;s/\n/\t/g;s/\t/, /g;s/,/\t/}' file
ID1     1, 5, 6, 8
ID2     1, 4, 5, 7

Hi,
Another sed solution (general):

Code:

$ cat iid.txt
ID1
1       5
6       8
ID2
1       4
5       7
5       7
5       7

ID3
1       4
$ sed  -e ':yy;/^[A-Z]/{s/$/\t/;:xx;$bzz;N;s/\(\n\|\t\)\([0-9]\)/,\2/g;txx;};h;s/.*\n//;x;s/,//;s/\n.*//p;x;tyy;:zz;s/,//' iid.txt
ID1     1,5,6,8
ID2     1,4,5,7,5,7,5,7

ID3     1,4