A computer obtains a command history and a plurality of file histories. The command history includes command logs of executed commands. The plurality of file histories each include timing information and a character string indicating a storage location of each file. The computer extracts key commands from the command history on basis of contents of the executed commands. The computer extracts first file histories corresponding to each of the key commands on basis of timing information included in a command log of each of the key commands and timing information included in the plurality of file histories. The computer stores the first file histories in association with a first key command corresponding to the first file histories. The computer selects characteristic words from first character strings included in the first file histories. The computer stores the characteristic words in association with the first key command.
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