Assistance need understanding SED backreferences/grouping

[YEPssss]

I have a dataset consisting of

n = number
The numbers can vary from a big integer to a floting point number
[tt]
n1 n2 n3 n4 n5 n6
dd-mm-yy,##.##,###.##,##.##,####.##,####,####.##
[/tt]
First objective is to change the order of the date, so that the line would look like this after processing:

[tt]
n1 n2 n3 n4 n5 n6
yy-mm-dd,##.##,###.##,##.##,####.##,####,####.##
[/tt]

For educational reasons it would be fun to se how it would look if one would like to change the order of the numbers (but that's optional and "only" to enlighten me and others facinated of SED).

 

[feherke]

Hi

sed 's/\([[:digit:]]\{1,2\}\)-\([[:digit:]]\{1,2\}\)-\([[:digit:]]\{1,2\}\)/\3-\2-\1/' /input/file

Feherke.

http://rootshell.be/~feherke/

 

[YEPssss]

Wauuu that was a quick response feherke ... I'll check by putting it inside the place especially reserved for this line in my SED script

 

[YEPssss]

Excellent feherke
will save me valuable time that I can spend playing with SED for other purposes.

SED is a damn fine & quick little thingie for such purposes

Thanks again

Johan

 

[feherke]

Hi

Not only for such purposes. There are gurus able to use it for much more :

http://aurelio.net/sed/sokoban/

Feherke.

http://rootshell.be/~feherke/

 

[PHV]

Another useful tool (awk):
awk '
BEGIN{FS=OFS=","}{if(split($1,a,/-/)==3)$1=a[3]"-"a[2]"-"a[1];print}
' /path/to/input > output

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[YEPssss]

PHV

I've used awk before in the past for similar but fell over SED for things in the category.

None of you tried having fun grouping/moving the numbers around after the date or even before the date yet though ;-)

I'm just using this example to get a better grasp/idea of the SED semantics/logic

I'll try and time both solutions on a big sample

 

[PHV]

For me, awk will be much easier for fields reordering ...

Hope This Helps, PH.
Want to get great answers to your Tek-Tips questions? Have a look at FAQ219-2884 or FAQ181-2886

 

[YEPssss]

PHV

Yes you're right on that account, but at times lean and mean is cute too

Johan