This is pretty simple to do. It’s also very usable if you just want to compare 2 files or different sections on the same file. Here’s what you do while in vi or vim.
Split screen horizontally

:split

The above code will split vi horizontally like the screenshot below. You can also supply an optional filename. If you [...]

Have you ever done SHOW FULL PROCESSLIST on MySQL and found that there are some queries that has been running for a long time? Then you tried to find out from where the query was initiated so that you can debug those script only to find out that there are many similar queries from different [...]

This is something I got "bitten" once, especially if you have a development server with its own database not replicated and production database is replicated. That slight difference is enough to cause production problems that may not be noticeable days after production release. As a wise man say:
When programming SQL statements, be mindful of replication.
Well, [...]

I mostly do programming by SSH-ing to development server. The code I’m working on are often managed by using SVN. There are many occasions when I need to search all source code to find a particular string. If you’ve worked on a source code that’s managed by SVN before, you’ll pretty soon notice that there [...]

There are times when I need to quickly gather some quick data in a simple tab based or space based delimited file, most often log files. Also, the files that I work on are often huge, well according to my standard at least … about 1GB. The data that I need is often simple statistics [...]