You mean something like this?
awk '{sub(/^\./, "", $1); printf(".%s", $1)}'This takes the first arg and looks for . at the beginning of the line and removes it and prints. The print happens regardless of the modification. In this example the input to this was the output of 'tar tf' being converted to an absolute location. I haven't use sub without a target recently. So off to the man page..... It operates on $0 which is the whole line and sub will operate on the longest matched string once per invocation meaning per line. On Tue, Jul 7, 2015 at 3:39 PM, Rich Shepard <[email protected]> wrote: > I understand sub(), gsub(), and substr() but have difficulty figuring > out > how to use any or all to modify a field's contents. > > Context: data files have variable numbers of fields per record; most of > these fields represent measured values as integers or (more often) as > floating point numbers. When a value is below the laboratory's method > detection limit they report the value with '<', '< ', or '-' preceeding the > floating point number. I want to strip off the leading symbol (with any > following white space) and retain the floating point number as the field's > content. > > It seems that sub() should do the job when I understand how to present > the > arguments to the function. The syntax is sub(regex, replacement [, > target]). > Not knowing if I can have if/elseif/elseif/else in the regex position my > initial approach is to use four calls to the function; e.g., > > sub(/\</,"") or sub(/\< /,"") > > Would these leave the remainder of the field's contents intact? gsub() > probably adds no more capabilities to solving this problem than does sub(). > Not sure if substr() is really appropriate here. > > I've read the two post-"The AWK Book" books I have and understand the > syntax but not how to apply the functions to achieve what needs to be done. > > This is just one issue that I need to grok while developing this generic > data cleaning program. > > Rich > _______________________________________________ > PLUG mailing list > [email protected] > http://lists.pdxlinux.org/mailman/listinfo/plug > _______________________________________________ PLUG mailing list [email protected] http://lists.pdxlinux.org/mailman/listinfo/plug
