AWK: Is there a way to limit the width of an output field?

Question

I need to limit the final size of a field to 2048. I could probably use:

ACTION_PARAMETER=substr($2,1,2048);

But is there a better way?

score 5 · Accepted Answer · answered Feb 27 '14 at 19:12

5

You could use printf

printf "%.2048s\n", $2

answered Feb 27 '14 at 19:12

user000001

Thanks for this. Since there haven't been any red flags brought up with my substr($2, 1, 2048), I'm going to stick with that for now. I am using a simple "print a, b, c, d" that is very long and I'd rather not restructure it with a printf if i don't need to. Thanks again. – D-Klotz Feb 27 '14 at 19:29

score 2 · Answer 2 · answered Feb 27 '14 at 19:12

2

Alternate way:

printf "%.2048s", $2

answered Feb 27 '14 at 19:12

anubhava

Please see my comment to user000001. Thanks for the answer. – D-Klotz Feb 27 '14 at 19:31

score 1 · Answer 3 · answered Feb 27 '14 at 19:13

1

You can play with the field separator FS being "" and then limiting the number of fields NF:

awk 'BEGIN{FS=OFS=""} NF=2048' file

$ cat a
hello
how are
you
i am ok

$ awk 'BEGIN{FS=OFS=""} NF=3' a
hel
how
you
i a

or even as a parameter:

$ awk -v limit=2 'BEGIN{FS=OFS=""} NF=limit' a
he
ho
yo
i

answered Feb 27 '14 at 19:13

fedorqui

I won't be able to use this trick. It's clever I'll grant that. In my case I have two audit log files I am processing with many fields of all different types and sizes. – D-Klotz Feb 27 '14 at 19:16
OK! If you need to use `FS` and `NF` in other parts, then my approach won't help, sure. – fedorqui Feb 27 '14 at 19:21

score 1 · Answer 4 · answered Feb 27 '14 at 19:43

1

How about native bash parameter slicing

printf "%s" ${2:0:2048}

answered Feb 27 '14 at 19:43

iruvar

4 Answers4