I would like to search my entire hard drive for some text that appears in regular files. I was given the following command, but I'm not sure it's doing exactly what I wanted. note: I'm trying to search for all the places that my old ip address appeared.

find / -type f -exec grep -H -i 69.69.69.69 {} \; 2>/dev/null

All I get with this results in some obscure files that are hidden or don't really pertain.

An IP address is a configuration data item. You shouldn't need to search the entire drive; just /etc where configuration files are stored.

Running find as user may produce many *permission denied* messages. Running find as root should not do so.

Su to root.

find /etc -name '*.*' -type f | xargs grep '69.69.69.69'

Does your machine get it's address via DHCP?

If it does there would be no configuration files that would contain the address. On the other hand, if your machine uses a static address then you would have config files that contain the address. These files are typically under your /etc directory and the commnad line could be changed to:

using -exec with find will be slower than using xargs because a grep process will be spawned for every file found. Using xargs, you'll only spawn one grep process for a large group of files, which can be a lot more efficient, especially if you have a lot of small files.

However the xargs command above will have problems when file names have white-space characters in them. You can ask find to de-limit it's output with the ASCII null character using the -print0 option, and tell xargs to expect this format with the -0 option.

grep will match "." against any character, but you're wanting to say a literal ".". With fixed strings like this, fgrep is slightly more optimised, so it should be preferred for large matches when you're not interested in regular expression patterns.

One more thing, specifiying the -name '*.*' will match all files with a . in. If you want all files, you simply don't need to specify a -name option.

So here's the modified command:
The -H option to fgrep says that the filename will be printed with any matched input line, even if there is only one input file. The input filename is printed by default if there is more than one input file, which is usually going to be the case with find + xargs, but I kept this because there is a small chance that the last invocation of fgrep by xargs might have just one file passed to it.