---
name: "bloom"
section: "1"
platform: "linux"
package: "golang-github-dcso-bloom-cli"
version: "0.2.4-3+b16"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/bloom"
---

# bloom(1)

utility to work with Bloom filters

## NAME

**bloom** - utility to work with Bloom filters

## SYNOPSIS

```
bloom [global options] command [command options] [arguments...]
```

## DESCRIPTION

**This is the main tool to interact with Bloom filters, e.g. to create, fill and** **query them.**

## BASIC USAGE

**To create a new Bloom filter with a desired capacity and false positive** **probability, you can use \`create\`:**

```
    #will create a gzipped Bloom filter with 100.000 capacity and a 0.1 % false positive probability
    bloom --gzip create -p 0.001 -n 100000 test.bloom.gz
```

**To insert values, you can use the insert** *command* **and pipe some input to it** **(each line will be treated as one value):**

```
    cat values | bloom --gzip insert test.bloom.gz
```

**You can also interactively add values to the filter by specifying the** **--interactive option:**

```
    bloom --gzip --interactive insert test.bloom.gz
```

**To check if a given value or a list of values is in the filter, you can use** **\`check\`:**

```
    cat values | bloom --gzip check test.bloom.gz
```

**This will return a list of all values in the filter.**

## ADVANCED USAGE

**Sometimes it is useful to attach additional information to a string that we** **want to check against the Bloom filter, such as a timestamp or the original** **line content. To make passing along this additional information easier within** **a shell context, the Bloom tool provides an option for splitting the input** **string by a given delimiter and checking the filter against the resulting** **field values.**

```
    # will check the Bloom filter for the values foo, bar and baz
    cat "foo,bar,baz" | bloom -s filter.bloom
    # uses a different delimiter (--magic-delimiter--)
    cat "foo--ac5ba--bar--ac5ba--baz" | bloom  -d "--ac5ba--" -s filter.bloom
    # will check the Bloom filter against the second field value only
    cat "foo,bar,baz" | bloom -f 1 -s filter.bloom
    # will check the Bloom filter against the second and third field values only
    cat "foo,bar,baz" | bloom -f 1,2 -s filter.bloom
    # will print one line for each field value that matched against the filter
    cat "foo,bar,baz" | bloom -e -s filter.bloom
    # will print the last field value for each line whose fields matched against the filter
    cat "foo,bar,baz" | bloom -e -s --pf -1 filter.bloom
```

**This functionality is especially handy when using CSV data, as it allows you** **to filter CSV rows by checking individual columns against the filter without** **having to use external tools to split and reassemble the lines.**

## COMMANDS

- **\* create**

  **Create a new Bloom filter and store it in the given file.**

- **\* insert**

  **Inserts new values into an existing Bloom filter.**

- **\* join, merge**

  **Joins two Bloom filters into one.**

- **\* check**

  **Checks values against an existing Bloom filter.**

- **\* set-data**

  **Sets the data associated with the Bloom filter.**

- **\* get-data**

  **Prints the data associated with the Bloom filter.**

- **\* show**

  **Shows various details about a given Bloom filter.**

- **\* help**

  **Shows a list of commands or help for one** *command*

## OPTIONS

- **--gzip, --gz**

  **compress bloom file with gzip**

- **--interactive, -i**

  **interactively add values to the filter**

- **--split, -s**

  **split the input string**

- **--each, -e**

  **print each match of a split string individually**

- **--delimiter value, -d value**

  **delimiter to use for splitting (default: ",")**

- **--fields value, -f value**

  **fields of split output to use in filter (a single number or a comma-separated list of numbers, zero-indexed)**

- **--print-fields value, --pf value**

  **fields of split output to print for a successful match (a single number or a comma-separated list of numbers, zero-indexed).**

- **--help, -h**

  **show help**

- **--version, -v**

  **print the version**