In particular, ipsec supplies the invoked command with a suitable PATH environment variable, and also provides IPSEC_DIR, IPSEC_CONFS, and IPSEC_VERSION environment variables, containing respectively the full pathname of the directory where the IPsec utilities are stored, the full pathname of the directory where the configuration files live, and the IPsec version number.
ipsec --help lists the available commands. Most have their own manual pages, e.g. ipsec_auto(8) for auto.
ipsec --version outputs version information about Linux FreeS/WAN. A version code of the form ``Uxxx/Kyyy'' indicates that the user-level utilities are version xxx but the kernel portion appears to be version yyy (this form is used only if the two disagree).
ipsec --versioncode outputs just the version code, with none of --version's supporting information, for use by scripts.
ipsec --copyright supplies boring copyright details.
ipsec --directory reports where ipsec thinks the IPsec utilities are stored.
ipsec --confdir reports where ipsec thinks the IPsec configuration files are stored.
HTML documentation shipped with the release, starting with doc/index.html. <http://www.freeswan.org/doc.html> may also be of use.