OBGREP(1) General Commands Manual (urm) OBGREP(1)

obgrepan advanced molecular search program using SMARTS

obgrep [OPTIONS] SMARTS-pattern filename

The obgrep tool can be used to search for molecules inside multi-molecule database files (e.g., SMILES, SDF, etc.) or across multiple files.

If only a filename is given, obgrep will attempt to guess the file type from the filename extension.

Print the number of matches
Full match, print matching-molecules only when the number of heavy atoms is also equal to the number of atoms in the SMARTS-pattern
format
Specifies input and output format, see obabel(1) for available formats
Only print the name of the molecules
#
Print a molecule only if the pattern occurs # times inside the molecule
Invert the matching, print non-matching molecules

Note that in all examples, the SMARTS pattern is enclosed in single quotes '...' to ensure it is not changed by the shell.

Print all the molecules with a methylamine group:

obgrep 'CN' database.smi

Print all the molecules without a methylamine group:

obgrep -v 'CN' database.smi

Print the number of molecules without a methylamine group:

obgrep -v -c 'CN' database.smi

Print methylamine (if it exists in the file):

obgrep -f 'CN' database.smi

Print methylamine and/or methanol (if they exist):

obgrep -f 'C[N,O]' database.smi
Print all molecules with aromatic carbon in all SMILES files in the directory (i.e., *.smi)
obgrep 'c' *.smi

obabel(1), obfit(1), obrotate(1).

The web pages for Open Babel can be found at: https://openbabel.org/

A guide for constructing SMARTS patterns can be found at: https://www.daylight.com/dayhtml/doc/theory/theory.smarts.html

The obgrep program was contributed by Fabien Fontaine

Open Babel is developed by a cast of many, including current maintainers Geoff Hutchison, Chris Morley, Michael Banck, and innumerable others who have contributed fixes and additions. For more contributors to Open Babel, see https://openbabel.org/docs/Introduction/thanks.html

Copyright (C) 1998-2001 by OpenEye Scientific Software, Inc.
Some portions Copyright (C) 2001-2007 by Geoffrey R. Hutchison and other contributors.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

May 26, 2026 Open Babel 3.2