Shell Programming and Scripting

When cut encounters consecutive delimiters it seems to count each instance as a field, at least with spaces. Is this typical behavior for any delimiter?

Code:

#:~$ ifconfig eth0 | grep HWaddr
eth0      Link encap:Ethernet  HWaddr 94:de:80:a7:6d:e1  
#:~$ ifconfig eth0 | grep HWaddr | cut -d " " -f 11
94:de:80:a7:6d:e1

Yes, with cut every occurrence of the delimiter separates a field.


--
The default delimiter in awk does not. Try:

Code:

ifconfig eth0 | awk '/HWaddr/{print $5}'

As a side note, if you want to know the mac assigned to an interface, in a Linux system just read it from /sys:

Code:

cat /sys/class/net/eth0/address

Much faster.

Thank you. Awk's default behavior is easy to grasp, but I am trying to understand this cut example in the book. Just trying to understand the counting principle at work here. It just seems a field pops out of nowhere. for example:

Code:

word1 word2

- one delimiter, two fields

Code:

word1  word2

- two consecutive delimiters in a row, 4 fields

Code:

word1   word2

- 3 consecutive delimiters in a row, 5 fields

Correct? In the first example the delimiter is not counted as a field, but with consecutive occurrences we simply count each one as an occurrence of a field.

No, there is always one more fields than delimiters.
Between consecutive delimiters there is an empty field.

Got it. Thank you all for the help. Marking as solved.

BTW some versions of cut has -F option that folds adjacent delimiters into one