How to view huge text file via Vi or gedit

Don't use a text editor for viewing text.

There are better tools:

View files with less (Scroll with Space, End, Home, PageUp, PageDown; Search with "/something" ; Leave with q).

From less manual:

Less does not have to read the entire input file before starting, so with large input files it starts up faster than text editors like vi (1).

Usage:

less wordlist.txt

Consider the use of less -n:

-n or --line-numbers:

Suppresses line numbers. The default (to use line numbers) may cause less to run more slowly in some cases, especially with a very large input file. Suppressing line numbers with the -n option will avoid this problem.

(thanks for suggesting -n option @pipe)

Use grep to get only the lines you're interested in:

# Show all Lines beginning with A:
grep "^A:"  wordlist.txt

# Show all Lines ending with x and use less for better viewing
grep "x$"  wordlist.txt | less

Use head or tail to get the first or last n lines

head wordlist.txt
tail -n 200 wordlist.txt

For editing text, refer to this question.

Often, just "grep" is enough to find what you need.

If you need more "context" around a particular line, then use "grep -n" to find the line numbers of the lines of interest, then use sed to print out a "chunk" of the file around that line:

$ grep -n 'word' file 
123:A line with with word in it 

$ sed -n '120,125p' file 
A line 
Another line
The line before
A line with with word in it 
The line after
Something else