Shell Programming and Scripting

Thanks .
I tested basic awk scripts in the night like

awk '$1 ~ /foo/ { print $0 }'

awk '$1 ~ /GPGGA/) { print $0 }'
awk 'BEGIN { RS = "/" } ; { if ($1 ~ /$GPGGA/) print $1 }'

awk '$1 ~ /$GPGGA/ { print $0 }'
awk 'BEGIN { RS = "/" } ;{ $1 ~ /GPGGA/ { print $0 }}'

gawk -F "," '$1=="$SDDBT" && $4 !="" { print $4}' NMEAfile >output

awk '-F,>ouput '/GPGGA/ {
_ = $(NF-2) s $2 s substr($4, 1, 2) s substr($4, 3) s $6
}
/SDDBT/ && $2 { print _, $4 }
' s=" "'

awk -F,>ouput '/GPGGA/ {
_ = $(NF-2) s $2 s substr($4, 1, 2) s substr($4, 3) s $6
}
/GPGGA/ && $2 { print _, $4 }

The issue is how to store data fields from a number of processed NMEA
records for postprocessing by another pipelined application.

One solution is getline var to read and process 2 records of
fields.

Another is getline var < file
awk '{
if (NF == 2 && $1 == "@include") {
while ((getline line < $2) > 0)
print line
close($2)
} else
print

command | getline

example
awk '{
if ($1 == "@execute") {
tmp = substr($0, 10)
while ((tmp | getline) > 0)
print
close(tmp)
} else
print
}'

}'

' s=" "
---------

command | getline var===
the examples come from excellent awk on-line manual.
----cs.utah.edu/dept/old/texinfo/gawk/gawk_22.html------

awk 'BEGIN {
"date" | getline current_time
close("date")
print "Report printed on " current_time
}'
Working with two dimensional array I can save a series of NMEA records for
postprocessing.
The issue is I have to process live data stream on-the-fly.

Is awk fit for a live data stream processing .
Gps tick is 1 sec.

Darius
Darius

Darius,

Which NMEA keywords are you interested in, what data do you want to extract and what format.

If you give the sentence keywords, what you want the output to look like it would be pretty trivial to get you started along the right path.

Thanks.
I need any data I can build routes, tracks, POI, waypoints, lead and so on.
So long, lat, time, speed, lead ..
Moe ideas to come soon.

Just reading NMEA manual.
Ok.
Today I can try to read senteces, filter them and filter fields in records.
To build tracks, routes I can print data to output or send to a file >

Replacing one data stream by another data stream based on filtering rules.

Frankly speaking I am looking for basic gps application to read such filtered data stream on-the-fly updating (refresh) a map...

First step is to write dialog script as a viewer of gps data.
Don't know if I can pipe awk | dialog script data refresh

Darius