The Entrez Programming Utilities (E-Utilities) are a suite of eight server-side programs supporting a uniform set of parameters used to search, link and download data from the Entrez databases. EInfo provides basic statistics on a given database, including the last update date and lists of all search fields and available links. ESearch returns the identifiers of records that match an Entrez text query, and when combined with EFetch or ESummary provides a mechanism for downloading the corresponding data records. ELink gives users access to the vast array of links within Entrez so that data related to an input set can be retrieved. By assembling URL or Simple Object Access Protocol calls to the E-utilities within simple scripts, users can create powerful applications to automate Entrez functions to accomplish batch tasks that are impractical using web browsers. Instructions for using the E-Utilities are found under the ‘Entrez Tools’ link on the NCBI home page.
