[Unix] less vs more vs vi

'less is more,  more or less'

The developer of 'less' utility Mark Nudelman joked that it is the reverse of more; and hence the name less.

While vi is a full scale text editor with power capabilities that could envy any text editor under the sun, more and less are text viewers.  They do not offer text editing capabilities as powerful as vi.

less is similar to more in the sense that it does the same job as more, however it is more advanced than more. less provided advanced capabilities to navigate through the text file.  Also, less uses a completely different approach for memory management with files.

While more loads the complete file in memory before display on the terminal,  less uses the swapping mechanism to display files. This results in faster load access time with large files.

The syntax to open a file with less is exactly same as more. less followed by the filename as shown below.
less mytextfile.txt

Navigating the file with less is very handy as it provides option to use up-down-right-left keys for browsing.  One can type in line number followed by 'g' to directly go to the line as shown in following example.
To directly go to line 37, one can type
37