The SubString package is an open-source set of Unix Shell scripts used for substring reduction and frequency consolidation of word n-grams of different length. In the process, the frequencies of substrings are reduced by the frequencies of their superstrings and a consolidated list with n-grams of different lengths is produced without an inflation of the overall word count. The functions performed by SubString will primarily be of interest to linguists working on formulaic language, multi-word sequences and similar phraseological phenomena.