Dear Friends The option -a 1 or -a 2 is not correct. Suppose you have two comma separated value files with 10 records each, joined on the first column. The second file has 6 records where there is no match on the joining column (first). Let's call the files today.txt and yesterday.txt
If you use this command "join -t, -1 1 -2 1 -a 2 -o 2.1 today.txt yesterday.txt" it should give ONLY the non pairing lines from yesterday. Instead, it prints all the lines from yesterday. I am copying here the contents of both files. cat today.txt 2012054455,8624520081,6529,0,201 2012067075,2013106025,6214,0,201 2012087388,8623689800,6214,2,201 2012088887,8623689800,6214,0,201 2012120319,9739789996,392A,0,201 2012121177,9739789996,392A,0,201 2012122869,2013700000,6006,0,201 2012140209,2013700000,6006,0,201 2012143002,2012339982,6529,0,201 2012149116,2012339982,6529,0,201 cat yesterday.txt 2012067075,2019269533,6664,0,201 2012087388,2012320000,6006,0,201 2012088887,8624520081,6529,0,201 2012140209,9733360000,392A,0,201 2012204272,2019269533,6664,0,201 2012226151,2018209998,954F,0,201 2012299682,2018209998,954F,0,201 2012324322,9733360000,392A,0,201 2012334444,2017809469,6664,0,201 2012389608,2012320000,6006,0,201
