MYANON(1)

MYANON(1) 💅

okay bestie, you found the myanon page — the MySQL dump anonymizer that's lowkey a whole vibe. ✨

🌸 NAME 🌸

myanon — MySQL dump anonymizer 🫶

✨ SYNOPSIS ✨

myanon -f config_file [-d]

💖 DESCRIPTION 💖

okay so myanon reads a MySQL dump (the kind mysqldump(1) makes) from standard input and writes an anonymized version to standard output. no cap.

Anonymization is deterministic: it uses HMAC-SHA256 keyed by a shared secret, so identical input values always produce the same anonymized output. this preserves referential integrity across foreign keys — iconic behavior, honestly.

myanon works on flat (numeric and text) fields and has built-in support for JSON fields. optional Python support lets you use custom anonymization functions (e.g. using faker). 💅

🎀 OPTIONS 🎀

• -f config_file — path to the configuration file. it's required, bestie.
• -d — enable debug mode. prints debug information to standard error.
• -v, --version — print version information and exit.
• -h, --help — print a usage summary and exit.

🦋 CONFIGURATION FILE 🦋

the configuration file is a text file with the following directives.

💖 Global directives 💖

• secret = 'key´ — HMAC secret, up to 64 characters.
• stats = 'yes|no´ — when set to yes, statistics are appended as SQL comments at the end of the output.
• pypath = 'path´ — directory where the Python script is located. may be relative or absolute. the environment variable PYTHONPATH can also be used. only available when compiled with Python support (--enable-python).
• pyscript = 'name´ — name of the Python script (without the .py extension). only available when compiled with Python support.

🎀 Tables block 🎀

the tables block lists tables and their anonymization rules:

tables = {
   `table` = {
     `field` = rule
     ...
   }
   `other_table` = truncate
}

table and field names are enclosed in backticks. tables may also be matched using a regular expression with the regex prefix:

regex `(prod|test)players` = {
   `lastname`  = texthash 20
   `firstname` = texthash 20
}

🌈 ANONYMIZATION RULES 🌈

the following anonymization rules are available. most rules can take an optional 'c´ suffix to handle multiple values within a single field, separated by character c. 👑

• texthash N — hash the value into a readable text string of N characters (max 32).
• inthash N — hash the value into a numeric string of N digits (max 32).
• emailhash 'domain' N — hash the value into an email address ending with domain, N characters long in total (max 32).
• fixed 'value´ — replace the field with a fixed value. quoting follows the field type (text fields are quoted, numeric fields are not). quoting can be overridden with the quoted or unquoted keyword before the value:

fixed 'myvalue'
fixed quoted '5'
fixed unquoted '0x1234'

• fixed null — replace the field with SQL NULL.
• key — tag this field as the key column. its anonymized value is remembered and can be referenced by appendkey or prependkey rules in other columns of the same table.
• appendkey 'prefix' — replace the field with prefix followed by the current key value. requires a key column in the same table.
• prependkey 'suffix' — replace the field with the current key value followed by suffix. requires a key column in the same table.
• appendindex 'prefix' — replace the field with prefix followed by the current row index (starting at 1).
• prependindex 'suffix' — replace the field with the current row index followed by suffix.
• substring N — truncate the field value to the first N characters.
• json { path 'jsonpath' = rule ... } — apply anonymization rules to specific paths within a JSON field. paths use dot notation for nested objects (e.g. address.street) and brackets for arrays (e.g. items[]). each path is followed by one of the rules above. example:

`data` = json {
    path 'email'           = emailhash 'example.com' 20
    path 'address.street'  = texthash 15
    path 'items[]'         = texthash 10
}

• pydef 'function' — call a custom Python function for anonymization. the function must be defined in the script specified by pyscript and accept a single parameter (the value to anonymize). only available when compiled with Python support.
• truncate — remove all INSERT and UPDATE statements for this table (table-level rule).

🌸 EXAMPLES 🌸

anonymize a dump file:

mysqldump mydb | myanon -f myanon.conf > mydb_anon.sql

create both a real encrypted backup and an anonymized backup from a single dump:

mysqldump mydb | \
  tee >(myanon -f myanon.conf | gzip > mydb_anon.sql.gz) | \
  gpg -e -r me@domain.com > mydb.sql.gz.gpg

✨ EXIT STATUS ✨

• 0 — successful completion.
• 1 — an error occurred (configuration error, parse error, etc.).

🔥 SEE ALSO 🔥

mysqldump(1)

💀 BUGS 💀

report bugs to <pierre.pomes@gmail.com> or at https://github.com/ppomes/myanon/issues.

👑 AUTHORS 👑

Pierre Pomes.

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okay bestie, that's the whole MYANON(1) page — this is myanon 0.8, dated 2026-02-05, and yes, it ate. mwah 💋