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output absolute path of the present working directory
I've seen a lot of overly complicated attempts at figuring out "where am I?" I think this is a part of the problem: type -a pwd force the use of the binary version of `pwd` instead of the built-in with "/bin/pwd -P" -P option provides an absolute path to the present working directory for the overly cautious type: $(which pwd) -P

Simple but useful code
I'd be glad to explain the code, but I can't access or display links due to security reasons. Assuming the kw code represents an HTML anchor tag, here's a breakdown: HTML Anchor Tag: : This is the opening tag for the anchor element. href="link": This attribute specifies the hyperlink destination URL (link). When clicked, the user's browser navigates to the provided URL. kw: This is the content displayed within the anchor tag. It can be text or an image. In this case, it's likely text that says "kw". : This is the closing tag for the anchor element.

reverse order of file

Find broken symlinks and delete them
If you don't want to delete them, but just want to list them, do $ find -L /path -type l If you want to delete them with confirmation first, do $ find -L /path -type l -exec rm -i {} + Using the -L flag follows symlinks, so the -type l test only returns true if the link can't be followed, or is a symlink to another broken symlink.

pattern match in awk - no grep
Rather than chain a string of greps together and pipe them to awk, use awk to do all the work. In the above example, a string would be output to stdout if it matched pattern1 AND pattern2, but NOT pattern3.

Which processes are listening on a specific port (e.g. port 80)
swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Query an NFS host for its list of exports

(Debian/Ubuntu) Discover what package a file belongs to
'dpkg -S' just matches the string you supply it, so just using 'ls' as an argument matches any file from any package that has 'ls' anywhere in the filename. So usually it's a good idea to use an absolute path. You can see in the second example that 12 thousand files that are known to dpkg match the bare string 'ls'.

List .log files open by a pid
Uses lsof to display the full path of ".log" files opened by a specified PID.

Resume an emerge, and keep all object files that are already built
For Gentoo: If you do not use this command, portage will fetch the source again, and rebuild the hole application from the top. This command make portage keep all files that ar allready built


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