bash - awk string inequality seemingly not working -

i have file want find lines column 3 , 4 differ. file looks like:

chr1:109506687  [t/g]   bot     top chr1:109506690  [t/g]   bot     top ... 

the code use find these lines

awk '$3 != $4 {print $0}' cardio-metabo_chip_11395247_a.txt | shuf -n 10 

problem using command results

rs3218791       [a/c]   top     top 

where column 3 , 4 same.

when use conditional equality, namely == no output, tells me awk never considers 2 columns $3 , $4 equal, despite them being so.

ps. using :set list in vim, file looks like:

chr1:109506687^i[t/g]^ibot^itop$ chr1:109506690^i[t/g]^ibot^itop$ .... 

my awk version gnu awk 3.1.8, can't imagine having anything. should have been right in 1.0

what might wrong?

though can't reproduce issue (see below), think you're evaluating values numerically rather strings (all nonempty strings —even "0"— numerically evaluate 1). try this:

awk '$3 != $4 "" {print $0}' test 

that concatenates $4 empty string , should therefore force desired string comparison.

---

i failed reproduce problem mawk 1.2 , gawk 4.0.1:

$ cat test chr1:109506687  [t/g]   bot     top chr1:109506690  [t/g]   bot     top rs3218791       [a/c]   top     top $ mawk '$3 != $4 {print $0}' test chr1:109506687  [t/g]   bot     top chr1:109506690  [t/g]   bot     top $ gawk '$3 != $4 {print $0}' test chr1:109506687  [t/g]   bot     top chr1:109506690  [t/g]   bot     top 

the shuf pipe shouldn't have it, nor should tabs vs spaces. (though safe, tried combinations in test.)

fun tip: {print $0} implied if there's 1 clause no action. therefore, awk '$3 != $4' same awk '$3 != $4 {print $0}' ... though sure you're not making code harder peers read.