Just find the Linux apropos that have never been used, and directly enter apropos [keyword] to view commands related to keyword functions. The command actually completes the search for descriptions of other commands, lists the relevant commands, and the commands that don't necessarily appear are what you want, but can help you recall useful commands from them.
Linux apropos use method, man apropos to see for himself.
Linux Apropos Example
Use Linux apropos to find and sort related commands:
Apropos sort alphasort [scandir] (3) - scan a directory for matching entries bsearch (3) - binary search of a sorted array bsearch (3p) - binary search a sorted table bunzip2 (1) - a block-sorting file compressor , v1.0.2 bunzip2 [bzcat] (1) - a block-sorting file compressor, v1.0.2 bunzip2 [bzip2] (1) - a block-sorting file compressor, v1.0.2 bunzip2 [ bzip2recover] (1) - a block-sorting file compressor, v1.0.2 bzip2 (1) - a block-sorting file compressor, v1.0.2 bzip2 [bunzip2] (1) - a block-sorting file compressor, v1.0.2 bzip2 [bzcat ] (1) - a block-sorting file compressor, v1.0.2 bzip2 [bzip2recover] (1) - a block-sorting file compressor, v1.0.2 comm (1) - compare two sorted files line by line iterator_info_s [netsnmp_iterator_info_s] (3) - Holds Iterator informatIon containing functions which should be called by the iterator_ Handler to loop over your data set and sort it in a snmp specific manner ldap_sort_entries (3) - ldap sorting routines ldap_sort_entries [ldap_sort] (3) - LDAP Sorting routines ldap_sort_entries [ldap_sort_strcasecmp] (3) - LDAP Sorting routines ldap_sort_entries [ldap_sort_values] (3) - LDAP Sorting routines ldap_sort_strcasecmp (3) - ldap sorting routines ldap_sort_strcasecmp [ldap_sort] (3) - ldap sorting routines ldap_sort_strcasecmp [ldap_sort_entries] (3) - ldap sorting routines Ldap_sort_strcasecmp&nbSp; [ldap_sort_values] (3) - ldap sorting routines ldap_sort_values (3) - ldap sorting routines ldap_sort_values [ldap _sort] (3) - ldap sorting routines ldap_sort_values [ldap_sort_ entries] (3) - ldap sorting routines ldap_sort_values [ldap_sort_ strcasecmp] (3) - ldap sorting routines lsort (n) - sort the elements of a list qsort (3) - sorts an array qsort (3p) - sort a table of&Nbsp;data sort (1) - sort lines of text files sort (1p) - Sort, merge, or sequence check text files sort (3pm) - perl pragma to control sort () behaviour texindex (1) - sort texinfo index files tsort (1) - perform topological sort tsort (1p) - topological sort uniq (1) - remove Duplicate lines from a sorted file versionsort [scandir] (3) - scan a directory for matching entries