如何用简洁awk命令去除第一列重复记录并保留其余列

Great question! Your initial awk approach is already on the right track, and we can definitely trim it down to a more concise one-liner while retaining all the functionality you need (preserving empty lines, keeping first occurrences of the first column, leaving other columns untouched).

Most Concise Version (Handles Empty Lines) #

awk '!NF{print;next}!($1 in a){a[$1];print}' file

Even Shorter (If No Empty Lines Need Preserving) #

If your input file doesn't have empty lines that you need to keep, you can simplify it to this ultra-clean command:

awk '!($1 in a){a[$1];print}' file

How It Works #

• The associative array a acts as a tracker: every time we encounter a new value in the first column ($1), we add it to a and print the entire line.
• For empty lines (where NF—number of fields—is 0), the first condition !NF{print;next} ensures we print them immediately without checking the array, preserving their place in the output.
• Subsequent lines with duplicate first-column values are skipped entirely, since $1 will already exist in a.

This maintains the original line order, keeps all other columns exactly as they are, and efficiently removes duplicates from the first column in a single pass through the file.

内容的提问来源于stack exchange，提问作者OXXO