UNIX for Dummies Questions & Answers

Code:

 awk -F/ '{a[$3]=$0;next}END{for(i in a) print a[i]}' filename

-Devaraj Takhellambam

I don't think next is needed in there

thanks devaraj, however it only gives me the last line of the file. would you explain about the code? thanks

You are right. next is not necessary here as it deals in the main loop with only one file.

What is your input like? The key to the above awk script is the third field. You may want to change it to suit your /p accordinlgy.

Code:

a[$3]=$0

this is my input file:
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0000.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0001.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0010.bmp
Data\DiStAnCe\DistanceSource\130 m\s1\130-s1-0002.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0011.bmp
Data\DiStAnCe\DistanceSource\130 m\s1\130-s1-0003.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0012.bmp
Data\DiStAnCe\DistanceSource\130 m\s1\130-s1-0004.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0034.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0035.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0036.bmp
Data\DiStAnCe\DistanceSource\130 m\s1\130-s1-0031.bmp

what i want to do is remove the previous line where its third field is similar with the third field of current line. by the way, my final goal is calculate the difference of numbers in lines of that file and get the average. so the result i want will be:

Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0010.bmp
Data\DiStAnCe\DistanceSource\130 m\s1\130-s1-0002.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0011.bmp
Data\DiStAnCe\DistanceSource\130 m\s1\130-s1-0003.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0012.bmp
Data\DiStAnCe\DistanceSource\130 m\s1\130-s1-0004.bmp
Data\DiStAnCe\DistanceDestination\130 m\d1\130-d1-0036.bmp
Data\DiStAnCe\DistanceSource\130 m\s1\130-s1-0031.bmp

then ...

010
002
011
003
012
004
036
031

then

8 (010-002, first line minus second line)
8 (011-003)
8 (012-004)
5 (036-031)

then

7.25 (average of them), this is the final result

i've been messed around with this problem for three days, and still i can't get what i want. would you or someone help me please ?. thanks