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Two columns A and B: Column A have repeated ids and column B has different values for each corresponding repeated value. I would like to read every uniq value from Column A with only the first hit from column B
File_B.txt
A 1 A 2 B 3 B 2 B 4 C 1 C 5 D 4 D 3 E 2
Output:
A 1 B 3 C 1 D 4 E 2
sort -k1,1 -u file
Sort file by first column and take first unique entry only.
sort -u can return incorrect result in locales which have collating characters sort the same. Example printf '%b\n%b\n' $'\U2460' $'\U2461' | LC_ALL=en_US.UTF-8 sort -u
With awk:
awk '!($1 in a){a[$1];print}' <file
or:
awk '!a[$1]++' <file
