A quick lookup in the
man pages gives us the following short description.
strings - find the printable strings in a object, or other binary, file
What’s inside /bin/ls?
$ strings /bin/ls ... %s%s %*u %-*s %-*s %-*s %3d, 0x%08x warn: LSCOLORS should use characters a-h instead of 0-9 (see the manual page) error: invalid character '%c' in LSCOLORS env var allow read list ...
This is just a snippet of strings for this particular binary. As you can see, we have some format strings, some errors and some other keywords.