NAME

esearch - search an NCBI Entrez database

SYNOPSIS

esearch (edirect -search) [-help] -db name -q[uery] str [-sort field] [-days N] [-datetype field] [-mindate date] [-maxdate date] [-field field] [-pairs field] [-spell]

DESCRIPTION

esearch searches an NCBI Entrez database for a given query.

It has two implementations: a shell implementation on top of nquire(1) and a traditional Perl implementation that amounts to running edirect -search, enabled by setting the environment variable USE_NEW_EDIRECT to a false value as described in the ENVIRONMENT section.

Some options are implementation-specific, as detailed below. In addition, the shell implementation accepts the full range of efilter(1) options, whereas the Perl implementation accepts only those specifically mentioned below.

OPTIONS

Query Specification

-db name: Entrez database name.
-q str (Perl implementation only)
-query str: Query string.

Document Order

-sort field: Sort results by the given field.

Date Constraint

-days N: Return only results from the past N days.
-datetype field: Which date field (in abbreviated form) to consider.
-mindate date: Start of date range.
-maxdate date: End of date range.

Limit by Field

-field field (Perl implementation only): Query words individually in field.
-pairs field (Perl implementation only): Query overlapping word pairs.

Spell Check

-spell: Correct misspellings in query.

Miscellaneous Arguments

-help: Print usage information.

ENVIRONMENT

USE_NEW_EDIRECT: Whether to use the current shell implementation or revert to the historical Perl implementation. Canonical true values are 1, on (case-insensitive), true (case-insensitive), and yes (case-insensitive); canonical false values are 0, off (case-insensitive), false (case-insensitive), and no (case-insensitive).