\name{elink}
\alias{elink}
\title{ Entrez database links }
\description{ Find links between Entrez databases at NCBI  }
\usage{
elink(id, cmd = "neighbor_history", parse = TRUE, ...)
}
\arguments{
  \item{id}{ An EntrezHistory object or vector of Ids }
  \item{cmd}{ Command mode }
  \item{parse}{  Parse results into an EntrezHistory object (default) or 
      vector of linked Ids (if cmd="neighbor").  All other cmd options return XML }
  \item{\dots}{ Other key-value pairs such as dbfrom, db, linkname  passed to the elink url string }
}
\details{ See \code{\link{einfo}} to find available links  }

\value{ Same as \code{\link{esearch}} }

\references{\url{http://www.ncbi.nlm.nih.gov/books/NBK25499} }
\author{ Chris Stubben}
\note{If EntrezHistory results are the input, then the database listed in that object is used as the \code{dbfrom} key. }
% \seealso{}
\examples{

elink("15718680,157427902", dbfrom="protein", db="gene")
elink("15718680,157427902", dbfrom="protein", db="gene", cmd="neighbor")
# list linknames
einfo("genome", TRUE)[, 1:2]
x <- esearch("Nipah virus", "genome")
# dbfrom is set to "genome" and default link is "genome_nuccore"  
y <- elink(x, db="nuccore")
y
# Links to reference AND genbank sequence the reference was derived from
esummary(y)
# OR link to Other genomes for Species
esummary( elink(x, db="nuccore", linkname="genome_nuccore_samespecies"))

}
\keyword{ methods }