audit_encode_nv_string - Linux


audit_encode_nv_string is a command-line tool for encoding case-insensitive null-terminated NUL-separated key-value string pairs into a binary format used by the Linux audit system. It is primarily used for serializing key-value pairs for storage or transmission in a manner that ensures data integrity and consistency.


audit_encode_nv_string [-h] [-q] [-s OUTPUT_FILE] [-i KEY_VALUE_FILE] [-S 'STRING1=STRING2'] ...


  • -h, –help: Display usage information and exit.
  • -q, –quiet: Suppress all non-error messages.
  • -s, –stdout: Write output to stdout instead of a file.
  • -i, –input: Read key-value pairs from the specified file.
  • -S, –string: Specify a key-value pair to encode as a string. Can be repeated for multiple pairs.


Encode a single key-value pair from a string:

audit_encode_nv_string -S "user=alice"

Encode key-value pairs from a file:

audit_encode_nv_string -i key_value_file

Encode multiple key-value pairs from strings:

audit_encode_nv_string -S "type=LOGIN" -S "user=alice" -S "host=server1"

Save encoded output to a file:

audit_encode_nv_string -i key_value_file -s encoded_file

Common Issues

  • Incorrect input format: Ensure that the input file or strings adhere to the NUL-separated key-value format.
  • Duplicate keys: Keys in the input should be unique. Duplicate keys may result in unexpected behavior.


audit_encode_nv_string can be used in conjunction with other Linux commands and tools, such as:

  • auditctl: To set or modify audit rules that specify key-value pairs for recording.
  • ausearch: To search for audit records containing specific key-value pairs.

Related Commands

  • auditctl
  • ausearch
  • auditd