See [File arguments vs. target arguments](🔗) for the normal techniques for telling Pants what to run on.
See [Project introspection](🔗) for queries that you can run and then pipe into another Pants run, such as running over certain target types.
## Running over changed files with `--changed-since`
Because Pants understands Git, it can find which files have changed since a certain commit through the `--changed-since` option.
For example, to lint all uncommitted files, run:
To run against another branch, run:
By default, `--changed-since` will only run over files directly changed. Often, though, you will want to run over any [dependees](🔗) of those changed files, meaning any targets that depend on the changed files. Use ` --changed-dependees=direct` or ` --changed-dependees=transitive` for this:
Using a version control system other than Git?
Please message us on Slack or open a GitHub issue (see [Community](🔗)). We would be happy to look into adding support for your VCS, such as helping you with a PR to add support.
## Tags: annotating targets
Every target type has a field called `tags`, which allows you to add a sequence of strings. The strings can be whatever you'd like, such as `"integration_test"`.
You can then filter by tags with the global `--tag` [option](🔗), like this:
To exclude certain tags, prefix with a `-`:
You can even combine multiple includes and excludes:
## `--spec-files`
The global option `--spec-files` allows you to pass a file containing target addresses and/or file names/globs to Pants.
Each entry must be separated by a new line.
For example:
Tip: centralized allow/block lists
Whereas `
tags` are useful for _decentralized_ allow/block lists, `--spec-files` is useful when you want to define one single list of targets or files.
## Piping to other Pants runs
To pipe a Pants run, use your shell's `|` pipe operator and `xargs`:
You can, of course, pipe multiple times:
Alternative: use `
--spec-files`Sometimes, you may want to reuse the output of a Pants run for multiple subsequent Pants runs. Rather than repeating `
xargs` multiple times, you can generate a file through stdout redirection and `--spec-files`.For example:
If you don't want to save the output to an actual file—such as to not pollute version control—you can use a variable and a named pipe:
## Sharding the input targets
You can leverage shell piping to partition the input targets into multiple shards.
For example, to split your Python tests into 10 shards, and select shard 0: