awk unexpectedly removes dot from string

Question

I want to add a column (2nd place) in a .csv file and I want the values of that column to be strings and to be quoted;

The following command does add the column but without quotes:

awk -F"," 'BEGIN { OFS = "," } {$2="2.4.0"; print}' test.csv > output.csv

The following approach does incorporate the quotes, but for some reason it removes the last . (dot) from the value

awk -F"," 'BEGIN { OFS = "," } {$2="\""2.4.0"\""; print}' test.csv > output.csv

so my values end up being "2.40".

How should I go about this?

Answer 1

You seem to have got the quotes wrong. You need to do as below

awk -F"," 'BEGIN { OFS = "," } {$2="\"2.4.0\""; print}' test.csv > output.csv

This is explained in the GNU awk man page - 3.2 Escape Sequences

Some characters cannot be included literally in string constants ("foo") or regexp constants (/foo/). Instead, they should be represented with escape sequences, which are character sequences beginning with a backslash (\). One use of an escape sequence is to include a double-quote character in a string constant. Because a plain double quote ends the string, you must use \" to represent an actual double-quote character as a part of the string..

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As far as the reason I could understand the reason for the behavior, awk seems to have interpreted 2.4.0 as a numeric word with the extra quotes from your OP and decides to lose the precision after the first dot.

i.e.

$2="\""2.4.0"\""

becomes just

$2=""2.4.0""

which awk no longer understands as a string. You can reproduce this behavior by simply doing

awk 'BEGIN { print ""2.4.0"" }'
2.40

which happens to be the result when you do

awk 'BEGIN { print 2.4.0 + 0 }'