Shell Programming and Scripting

Dear All,
I really enjoy your help or suggestion for resolving an issue.
Briefly, I have a file like this:

Code:

a b c
a d e 
f g h
k g h 
x y z

If the first column has the same ID, for example

Code:

a

, just remove it.
The output should be this:

Code:

f g h 
k g h 
x y z

I was thinking to do it with

Code:

uniq

for column1 and then

Code:

grep

the results obtained.
I mean, it works basically, but if you have some other solution I ll be grateful.

Best

Giuliano

Hello giuliangiuseppe,

Could you please try following and let me know if this helps you.
1st: If you doesn't care about order as per your Input_file:

Code:

awk '{A[$1]=$0} END{for(i in A){print A[i]}}'  Input_file

2nd: If you need output in same order as Input_file then following may help you in same.

Code:

awk 'FNR==NR{A[$1]=$0;next} ($1 in A){print A[$1];delete A[$1]}'  Input_file  Input_file

Thanks,
R. Singh

Hi there,
thank you for reply and suggestion.
well, maybe my explanation was awful (probably!!) my I d like to remove completely the duplicate ID in column 1 and relative rows. If an IDs in column 1 compare more that 1 time, remove all the line with that IDs.

best

G

Hello giuliangiuseppe,

Could you please try this and let me know if this helps you.

Code:

awk 'FNR==NR{A[$1]=$0;B[$1]++;next} {if(B[$1]==1){print $0}}'  Input_file  Input_file

Output will be as follows.

Code:

f g h
k g h
x y z

Thanks,
R. Singh

perfect!

This could be shortened to:

Code:

awk 'NR==FNR{A[$1]++; next} A[$1]==1' file file

Hi Scrutinizer just a question because I am learning awk.
Does you command suppose that the input file should be sorted by the column 1?
Or not?

thank you