You will not normally modify this file. For the sake of completeness, the format of the file is described here.
The scanps_alias.dat file allows aliases to be defined for any of the valid commands. For example, here is an excerpt from scanps_alias.dat.
MAX_NSEQ max_nseq #Maximum number of sequences allowed TIME time #Set to 1 to record CPU times MODE mode #Type [scanps HELP modes] to see available modes QSEQ_FORMAT QSEQ_F qseq_format qseq_f #0 = PIR format, 1 = FASTA format DB_FORMAT DB_F db_format db_f #As for QSEQ_FORMAT MAX_SEQ_LEN max_seq_len #Max allowed length for an amino acid sequence
Each command name is followed by a list of aliases, then a # followed by some optional descriptive text.