> For the complete documentation index, see [llms.txt](https://docs.hex-rays.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hex-rays.com/ida-actions/loadsigfile.md).
# LoadSigFile
## Description
Load a FLIRT signature file. This command allows you to apply an additional signature file to the program. A signature file contains patterns of standard runtime functions. With their help, IDA is able to recognize the standard functions and names them accordingly. IDA attempts to detect the necessary signature files automatically but unfortunately, this is not always possible. This command adds the specified signature file into the planned signature files queue. Signature files reside in the subdirectories of the SIG directory. Each processor has its own subdirectory. The name of the subdirectory is equivalent to the name of the processor module file (z80 for z80.w32, for example). Note: IBM PC signatures are located in the SIG directory itself. Note: the IDASGN environment variable can be used to specify the location of the signatures directory.
There is another way to load a signature file: you may insert/delete signature files in the following way:
* open the signatures window
* press Ins to insert a signature file to the queue
* press Del to delete a signature file from the queue
This is a preferred way of applying signatures because useful information, such as the number of identified functions is displayed in the signature window.
{% hint style="info" %}
FLIRT works only for the processors with normal byte size. The byte size must be equal to 8 (processors with wide bytes like AVR or DSP56K are not supported)
{% endhint %}
---
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