A4-Tacks
4beed4e01a
Define `from_entries` as `add(.[] | f) // {}` instead of
`map(f) | add // {}`. Since `add(f)` is `reduce f as $x (null; . + $x)`,
both fold the same values in the same order from the same seed, so the
only difference is that the array of single-key objects built by `map`
is never materialized.
Measured with both the generator and the result suppressed, so that only
the `from_entries` work differs: 6-15% less user time across input shapes,
which is 10-24% of what `from_entries` itself costs. For inputs above
roughly a thousand entries, peak RSS drops by 37%, around 80% of the
memory `from_entries` adds on top of its input; a 1,000,000 entry array
goes from 1064 MiB to 672 MiB.
jq
jq is a lightweight and flexible command-line JSON processor akin to sed,awk,grep, and friends for JSON data. It's written in portable C and has zero runtime dependencies, allowing you to easily slice, filter, map, and transform structured data.
Documentation
- Official Documentation: jqlang.org
- Try jq Online: play.jqlang.org
Installation
Prebuilt Binaries
Download the latest releases from the GitHub release page.
The platform-specific assets are standalone executables, not archives. On macOS and Linux,
rename the downloaded file to jq and make it executable with chmod +x jq.
Docker Image
Pull the jq image to start quickly with Docker.
Run with Docker
Example: Extracting the version from a package.json file
docker run --rm -i ghcr.io/jqlang/jq:latest < package.json '.version'
Example: Extracting the version from a package.json file with a mounted volume
docker run --rm -i -v "$PWD:$PWD" -w "$PWD" ghcr.io/jqlang/jq:latest '.version' package.json
Building from source
Dependencies
- libtool
- make
- automake
- autoconf
Instructions
git submodule update --init # if building from git to get oniguruma
autoreconf -i # if building from git
./configure --with-oniguruma=builtin
make clean # if upgrading from a version previously built from source
make -j8
make check
sudo make install
Build a statically linked version:
make LDFLAGS=-all-static
If you're not using the latest git version but instead building a released tarball (available on the release page), skip the autoreconf step, and flex or bison won't be needed.
Cross-Compilation
For details on cross-compilation, check out the GitHub Actions file and the cross-compilation wiki page.
Community & Support
- Questions & Help: Stack Overflow (jq tag)
- Chat & Community: Join us on Discord
- Wiki & Advanced Topics: Explore the Wiki
License
jq is released under the MIT License. jq's documentation is
licensed under the Creative Commons CC BY 3.0.
jq uses parts of the open source C library "decNumber", which is distributed
under ICU License