Bugs can affect the normal usage of a software system or even bring huge damages. In order to facilitate developer to find and fix bugs as soon as possible, information retrieval based bug localization techniques have been proposed. This kind of techniques regards bug localization as a task of text retrieval. Specifically, for a given bug report, a rank list of code entities in a descending order is provided according to relevance score between code entity and the bug. Developers can select entities in the rank from top to bottom, which helps reducing the review cost and accelerating the process of bug localization. In recent years, a great progress has been achieved in information retrieval based bug localization techniques. Nevertheless, it is still challenging to apply them in practice. This survey offers a systematic overview of recent research achievements in information retrieval based bug localization techniques. First, the research problem is introduced in information retrieval-based bug localization. Then, the current main research work is described in detail. After that, the related techniques are discussed. Finally, the opportunities and challenges are summarized in this field and the research directions in the future are outlined.