Shell Programming and Scripting

Red    4
Red    5
Red    10
Black   33
Black   44
Black   5
Green  2
Green 55
Green 78

Red   4
Black 5
Green 2

awk '!a[$1]{a[$1]=$2} $2<a[$1]{a[$1]=$2} END{for(i in a)print i, a[i]}' file

# myFile="TestFile.txt"
# numDiff=`cut -f1 -d" " "${myFile}" | sort | uniq | wc -l`
# sort -n -k2 "${myFile}" | head -"${numDiff}"
Green 2
Red 4
Black 5

## Or in one!
# sort -n -k2 "${myFile}" | head -`cut -f1 -d" " "${myFile}" | sort | uniq | wc -l`

AAAAAAAAAC 46 _ Hs.621716
AAAAAAAAAC 46 AA636074 _
AAAAAAAAAC 77 AI861786 _
AAAAAAAAAC 77 BE536886 _
AAAAAAAAAC 77 BE548727 _
AAAAAAAAAC 77 BF691443 _
AAAAAAAAAC 79 BF754052 _
AAAAAAAAAC 80 BI004369 _
AAAAAAAAAC 86 BU535655 _
AAAAAAAAAC 86 BU539770 _
AAAAAAAAAC 86 BX111054 _
AAAAAAAAAC 86 BX643752 _
AAAAAAAAAC 86 CA390277 _
AAAAAAAAAC 94 CD522477 _
AAAAAAAAAC 94 DR159089 _
AAAAAAAAAG 5 _ Hs.190440
AAAAAAAAAG 26 _ Hs.445936
AAAAAAAAAG 46 _ Hs.567437
AAAAAAAAAG 74 _ Hs.674701
AAAAAAAAAG 77 _ Hs.700965
AAAAAAAAAG 77 AI034458 _
AAAAAAAAAG 77 AV699522 _
AAAAAAAAAG 77 AV719142 _
AAAAAAAAAG 79 AW150843 _
AAAAAAAAAG 80 AW801953 _
AAAAAAAAAG 80 AW857024 _
AAAAAAAAAG 86 BC033980 Hs.721040
AAAAAAAAAG 86 BE072635 _
AAAAAAAAAG 86 BF104499 _
AAAAAAAAAG 86 BF897128 _
AAAAAAAAAG 93 BG537298 _
AAAAAAAAAG 93 BG706646 _
AAAAAAAAAG 94 BI025564 _
AAAAAAAAAG 94 BX425052 _
AAAAAAAAAG 100 F24242 _

AAAAAAAAAC 46 _ Hs.621716
AAAAAAAAAG 5 _ Hs.190440

AAAAAAAAAC 46
AAAAAAAAAG 5