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directory
A Unix file that contains names of other files or directories. More technically, a system-managed file containing the associations between path components and inodes.
Each directory entry contains an inode number and a path component.
directory hierarchy
The arrangement of directories in a Unix file system, consisting of a root directory at
the top of the directory hierarchy containing pointers to all file systems, and hence to
all directories on the system.
disk partition
Part of a disk onto which a file system is mounted.
driver
The device dependent code for a particular device class; eg: a specific type of printer
or terminal.
environment
The set of characteristics describing a user’s sessions, including open files, user and
group identification, process identification and environment variables.
environment variable
A variable exported automatically to subsequent programs.
EOF
End-of-file generated by <ctrl-d> or the end of a file used as input.
escape
A special character (0x1b) initiating command sequences for terminals and programs.
A metacharacter is said to be ’escaped’ when preceded by the character ’\’ to make
the metacharacter lose its special meaning.
ethernet
A packetised asynchronous protocol using coaxial or optical fiber cable with multiple
senders and receivers. Each node listens for packets which are addressed to it. When a
node wants to send, it waits for the ethernet to be idle and then sends. If two or more
nodes attempt to send at the same time, they detect this condition by checking their
own signals as they come back to the node and if the signals are damaged each node
waits for a short random amount of time and then tries again.
event
Past command stored in the history list.
exec
A family of system calls that replace one program executing in a process with another.
The system calls differ in format of the arguments and not in the purpose of the system call.
expansion
The replacement of strings in the shell input which contain metacharacters by other
strings.
file
A collection of data known to the operating system. In most operating systems a file is
associated with a specific name or names. In Unix a file need not have a name but
most files do at least have one.
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