You can do many things in UNIX command line using Perl and "wc".

Counting the number of sequences:

grep '>' INPUT.fasta | wc -l

Counting the total length of all sequences:

grep -v '>' INPUT.fasta | perl -pe 's/[\n\r]//g' | wc -c

List of all sequence lengths:

cat INPUT.fasta |\
perl -pe '/^>/ ? s/.*// : s/[\n\r]//g' |\
tail -n +2 |\
perl -pe 's/.*/length($&)/e'