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Removing duplicates with awk

To remove duplicates in linux you can use awk command as follows:

 awk -F- '!seen[$1]++' file.txt > output.txt

where:

-F is paraeter to deternime separator used to define columns and in ths case the dash 8-) is the sparator used

'!seen[$1]++' is the expression used for the line in order to be printed

> is the instruction to send command output o a file
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