scan is one of the two command line frequency scanning utilities contained in the LinuxTV dvb-apps. The other one is dvbscan. There are also two utilities, not included in LinuxTV dvb-apps, called w_scan and scan-s2. Comparison of the scanning utilities.
When using scan, one indirectly instructs it to search for programs streams that can be received from specified frequencies and generates a resultant channel list.
scan does not have a man page. However, if you run it with the -h parameter, the output provides a summary of its command options. For example, running scan -h produces:
usage: scan [options...] [-c | initial-tuning-data-file] atsc/dvbscan doesn't do frequency scans, hence it needs initial tuning data for at least one transponder/channel. -c scan on currently tuned transponder only -v verbose (repeat for more) -q quiet (repeat for less) -a N use DVB /dev/dvb/adapterN/ -f N use DVB /dev/dvb/adapter?/frontendN -d N use DVB /dev/dvb/adapter?/demuxN -s N use DiSEqC switch position N (DVB-S only) -i N spectral inversion setting (0: off, 1: on, 2: auto [default]) -n evaluate NIT-other for full network scan (slow!) -5 multiply all filter timeouts by factor 5 for non-DVB-compliant section repitition rates -o fmt output format: 'zap' (default), 'vdr' or 'pids' (default with -c) -x N Conditional Access, (default -1) N=0 gets only FTA channels N=-1 gets all channels N=xxx sets ca field in vdr output to :xxx: -t N Service select, Combined bitfield parameter. 1 = TV, 2 = Radio, 4 = Other, (default 7) -p for vdr output format: dump provider name -e N VDR version, default 3 for VDR-1.3.x and newer value 2 sets NIT and TID to zero Vdr version 1.3.x and up implies -p. -l lnb-type (DVB-S Only) (use -l help to print types) or -l low[,high[,switch]] in Mhz -u UK DVB-T Freeview channel numbering for VDR -P do not use ATSC PSIP tables for scanning (but only PAT and PMT) (applies for ATSC only) -A N check for ATSC 1=Terrestrial [default], 2=Cable or 3=both -U Uniquely name unknown services