CODEWITHSUNDEEP
linuxbashshellawkscripting
Redson
Redson

Reputation: 2140

How to check if a file is empty using awk in a bash script?

I am trying to check if a file is empty using awk in a bash script. This condition for a file being empty is the following: If a file only has its first row with field values followed by ------ (and followed by nothing else) then it is considered empty.

Here is the structure of that special file:

file.txt

col1   col2   col3   col4   col5
------

So far this is what I have:

awk '
    {
      if (NR > 2)
        print "NOT EMPTY"
      else
        print "EMPTY"
    }
' file.txt

The output I want is:

EMPTY

The empty I am getting is:

EMPTY
EMPTY

How do I get only EMPTY as one output? I know it might be very simple but I couldn't find anything. Thanks!

Let me know if further explanation is needed.

EDIT: Also, if extra blank lines are added to file.txt, then it will print EMPTY for as many extra line there is. Is there a more general approach to this?

Upvotes: 4

Views: 5736

Answers (2)

Ell
Ell

Reputation: 947

awk 'END{print(NR>2)?"NOT EMPTY":"EMPTY"}'

Upvotes: 6

anubhava
anubhava

Reputation: 786091

You need to put your awk logic in END block otherwise it is executed for each line of input:

awk '
    END {
      if (NR > 2)
        print "NOT EMPTY"
      else
        print "EMPTY"
    }
' file.txt

Upvotes: 6

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