Subject: make blindingly clear cut -f 2,1 = cut -f 1,2

From: 積丹尼 Dan Jacobson <[email-masked]>
Date: Sat, 05 Nov 2016 19:31:32 +0800

$ info cut

‘-f FIELD-LIST’
‘--fields=FIELD-LIST’
     Select for printing only the fields listed in FIELD-LIST.  Fields
     are separated by a TAB character by default.  Also print any line
     that contains no delimiter character, unless the ‘--only-delimited’
     (‘-s’) option is specified.

     Note ‘awk’ supports more sophisticated field processing, and by
     default will use (and discard) runs of blank characters to separate
     fields, and ignore leading and trailing blanks.
          awk '{print $2}'    # print the second field
          awk '{print $NF-1}' # print the penultimate field
          awk '{print $2,$1}' # reorder the first two fields

Mention here:
        whereas cut -f 2,1 will just give you the same output as cut -f 1,2
Thanks.

     In the unlikely event that ‘awk’ is unavailable, one can use the
     ‘join’ command, to process blank characters as ‘awk’ does above.
          join -a1 -o 1.2     - /dev/null # print the second field
          join -a1 -o 1.2,1.1 - /dev/null # reorder the first two fields