Extra space in awk output

问题

Why do I get the white space before and after the delimiter in the following example?

awk -F'^'  '{print $1,":",$2}' SERVER_2012-02-29-12-15-00
3969 : 1272
3969 : 1272
3969 : 1272

I expect the results as below without any space:

3969:1272
3969:1272
3969:1272

The text file looks like this...

cat SERVER_2012-02-29-12-15-00
3969^1272^14.140.90.242^^IN^como^2012-02-29
3969^1272^14.140.90.242^^IN^como^2012-02-29
3969^1272^14.140.90.242^^IN^como^2012-02-29

回答1:

This might work for you:

awk -F'^'  '{print $1":"$2}' SERVER_2012-02-29-12-15-00
3969:1272
3969:1272
3969:1272

To concatenate the fields with a : remove the ,'s.

Or change the output field separator OFS to null.

awk -F'^' -vOFS='' '{print $1",:,"$2}' SERVER_2012-02-29-12-15-00
3969:1272
3969:1272
3969:1272

回答2:

Solutions have been given, but no complete explanation...

It is because when you use print with many parameters (separated by coma) it puts a Field Separator between the values. From the awk man:

print expr-list

Print expressions. Each expression is separated by the value of the OFS variable. The output record is terminated with the value of the ORS variable.

The string concatenation operator in awk is not coma, neither +, but space: str = str1 str2 concatenate str1 and str2.

来源：https://stackoverflow.com/questions/9511803/extra-space-in-awk-output