Linux

fd = open(filename, flags, mode);
unlink(filename);
...
close(fd);

To include .tex files in subdirs in the main.tex file:

In main.tex:
\documentclass{article}
\begin{document}
...
\input{path1/submain.tex}
...
\end{document}

where submain.tex is of the form:

\section{Another Section}
\def\thisdir{path1/}
\input{\thisdir file1}
\input{\thisdir file2}

Better to include '/' in $thisdir because, later, $thisdir may be set to {}.

To create a file of size 'x' KB containing random data:

localhost% dd if=/dev/urandom of=random.file bs=1024 count=x

See man 4 (u)random for difference between using /dev/random and /dev/urandom.

To install a USB flash drive in Linux...

(on a Dell Dimension 3000 running Debian 3.1 Linux 2.6.9)

> modprobe usb-storage
> modprobe ide-scsi

now check the file /proc/partitions to find out the entry to use in /dev.
In my case, it was /dev/uba and /dev/uba1 with major number 125.
So,

> mknod /dev/uba b 125 0
> mknod /dev/uba1 b 125 1

> mkdir /mnt/flash
> mount -t vfat /dev/uba1 /mnt/flash

and that was it.