---
title: "Notes about the configuration syntax"
url: "https://axoflow.com/docs/axosyslog-core/4.28/chapter-configuration-file/configuration-syntax-notes/"
last_modified: "2023-07-02T20:37:04+02:00"
---

> For the complete documentation index, see [llms.txt](https://axoflow.com/docs/axosyslog-core/4.28/llms.txt).

# Notes about the configuration syntax

When you are editing the `syslog-ng.conf` configuration file, note the following points:

- The configuration file can contain a maximum of 6665 source / destination / log elements.
- When writing the names of options and parameters (or other reserved words), the hyphen (`-`) and underscore (`_`) characters are equivalent, for example, `max-connections(10)` and `max_connections(10)` are both correct.
- Numbers can be prefixed with `+` or `-` to indicate positive or negative values. Numbers beginning with zero (`0`) or `0x` are treated as octal or hexadecimal numbers, respectively.

  Starting with AxoSyslog version 3.5, you can use suffixes for kilo-, mega-, and gigabytes. Use the Kb, Mb, or Gb suffixes for the base-10 version, and Kib, Mib, or Gib for the base-2 version. That is, 2MB means 2000000, while 2MiB means 2097152. For example, to set the `log-msg-size()` option to 2000000 bytes, use `log-msg-size(2Mb)`.
- You can use commas (`,`) to separate options or other parameters for readability, AxoSyslog completely ignores them. The following declarations are equivalent:

  ```shell
      source s_demo_stream {
          unix-stream("<path-to-socket>" max-connections(10) group(log));
      };
      source s_demo_stream {
          unix-stream("<path-to-socket>", max-connections(10), group(log));
      };
  ```
- When enclosing object IDs (for example, the name of a destination) between double-quotes (`"mydestination"`), the ID can include whitespace as well, for example:

  ```shell
      source "s demo stream" {
          unix-stream("<path-to-socket>" max-connections(10) group(log));
      };
  ```
- For notes on using regular expressions, see [Regular expressions](https://axoflow.com/docs/axosyslog-core/4.28/chapter-manipulating-messages/regular-expressions/index.md).
- You can use `if {}`, `elif {}`, and `else {}` blocks to configure conditional expressions. For details, see [if-else-elif: Conditional expressions](https://axoflow.com/docs/axosyslog-core/4.28/chapter-routing-filters/logpath/concepts-if-else-conditional-expressions/index.md).

Last modified July 2, 2023: [Change highlight mode of code examples (2f8a9593)](https://github.com/axoflow/axosyslog-core-docs/commit/2f8a95937c6498193e7168ce8b0dc831e9f0f8ad)