#Basic AWK Part II: Slightly more advanced AWK 
#Written by E Heppenheimer, Spring 2018 

#Using AWK to extract entire rows based on value of certain column 
#For example, in a tab separated file, Column 1 is the chromosome ID and you want to pull out just chromosome 14 
#I like to be in the habit of specifying the field separator (-F)
#But, this is technically not necessary unless the field separator is something other than white space (i.e. NOT a space or a tab)

$ awk -F "\t" '$1 == 14 ' infile > chromosome14_only.txt 

#or for some reason you only want to keep lines where column 8 is equal to 26 

$ awk '$8 == 26 ' infile > outfile

#and so on... 

#It is also possible to specify a range of values
#e.g. only keep rows where column 12 is greater than or equal to 0.19 

$ awk ' $12 >=0.19 ' infile > outfile

#or less than 0.25 
$ awk ' $12 < 0.25 ' infile > outfile

#This also works for strings (that is, column X does not have to be a number) 

$ awk -F "\t" '$1 == "chr4"' infile > outfile