Commands using sort (800)

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generate 30 x 30 matrix
Replaces hexdump with the more succint xxd, and the sed was unnecessarily complex.

multiline data block parse and CSV data extraction with perl
extract data in multiline blocks of data with perl pattern matching loop

check open ports without netstat or lsof

For finding out if something is listening on a port and if so what the daemon is.
See what's listening on your IPv4 ports on FreeBSD.

Check (partial) runtime-dependencies of Gentoo ebuilds
The output is only partial because runtime dependencies should count in also commands executed via system() and libraries loaded with dlopen(), but at least it gives an idea of what a package directly links to. Note: this is meaningful *only* if you're using -Wl,--as-needed in your LDFLAGS, otherwise it'll bring you a bunch of false positives.

Determine if a command is in your $PATH using POSIX
it is generally advised to avoid using which(1) whenever possible. which(1) is usually a csh(1) script, or sometimes a compiled binary. It's output is highly variable from operating system to operating system, so platform independent scripts could become quite complicated with the logic. On HP-UX 10.20, for example, it prints "no bash in /path /path /path ..."; on OpenBSD 4.1, it prints "bash: Command not found."; on Debian (3.1 through 5.0 at least) and SuSE, it prints nothing at all; on Red Hat 5.2, it prints "which: no bash in (/path:/path:...)"; on Red Hat 6.2, it writes the same message, but on standard error instead of standard output; and on Gentoo, it writes something on stderr. And given all these differences, it's still variable based on your shell. This is why POSIX is king. See http://mywiki.wooledge.org/BashFAQ/081 for more ways on avoiding which(1).

Detect illegal access to kernel space, potentially useful for Meltdown detection
Based on capsule8 agent examples, not rigorously tested

Get your outgoing IP address

Extract all GPS positions from a AVCHD video.

To print a specific line from a file
You can get one specific line during any procedure. Very interesting to be used when you know what line you want.


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