Sift Version 0.9 Released

A new version of sift is now available for download:

sift 0.9 supports several new options:


The --conf option can be used to specify an additional config file. Settings configured in that file override settings from global/local config files.

This is especially useful in combination with the --no-conf option to use a specific configuration in scripts.


The --field-sep option allows to use a custom field separator, this can be useful when the output of sift is processed by another script.

$ sift PM_SUSPEND linux-kernel -n --field-sep '|'
linux-kernel/kernel/cpu.c|644|  case PM_SUSPEND_PREPARE:


This option allows to show the byte offset of the matching line. If this options is combined with --only-matching, it shows the offset of the match.

Support for custom types

sift supports types to limit searches to specific file types for quite some time now:

# only search in perl files (*.pl, *.pm, *.pod, *.t or a perl shebang on the first line):
$ sift -t perl pattern
# Exclude html and xml files: 
$ sift -T html,xml pattern

As of version 0.9, custom types can be created in addition to the built in types.

The following example creates a type script that searches in *.pl, *.py and *.rb files:

sift --add-type 'script=*.pl,*.py,*.rb' --write-config

Without the option --write-config the created type would only be valid for the current call to sift.

The option --list-types can be used to list all builtin and custom types. It also shows some sample commands to create custom types.

Performance improvements and better cross platform support

Sift is written in Go, and many things can be implemented with a good performance in Go. There are some limitations though - e.g. iterating over an array/slice includes bounds check to detect out of range errors. This can have a massive performance impact on tight loops.

Regarding sift, this affected the counting of newlines (only used when sift shows line numbers for matches) and a lowercase conversion routine. Up to sift 0.8, these routines were implemented in pure Go and alternatively in C. The C version performed better, but it had some overhead per function call (using cgo needs to translate between Go and C) and external dependencies (a C compiler).

As of version 0.9, the cgo dependency is removed. In addition to the pure Go implementations, sift now includes optimized assembly routines using SIMD instructions for 64-bit x86 processors. The assembly implementation gives a 20x speedup compared to the pure Go implementation on CPUs I tested. In practice this means that for processing very large files with line numbers turned on, runtime is cut in half.