sqlite3 command-line shell implements an additional set of commands (which are not available in programs that use the SQLite library). Official documentation: Special commands to sqlite3
Exporting a database is a simple two step process:
sqlite> .output mydatabase_dump.sql
sqlite> .dump
Exporting a table is pretty similar:
sqlite> .output mytable_dump.sql
sqlite> .dump mytable
The output file needs to be defined with .output prior to using .dump; otherwise, the text is just output to the screen.
Importing is even simpler:
sqlite> .read mytable_dump.sql