Unix System : Practice Questions and Answers

sed, tail, and cut are standard UNIX text-processing utilities, whereas wart is not a standard UNIX command.

The chmod go-w command removes (-) the write (w) permissions for both the group (g) and others (o).

UNIX strictly follows the philosophy that "everything is a file", meaning hardware devices are accessed and treated just like regular files via device nodes in the /dev directory.

The mmap system call is used for memory management in UNIX to map files or devices into memory.

The /usr directory is a standard UNIX directory that contains user utilities and applications.

The nice command can adjust a process's scheduling priority up or down by modifying its "niceness" value.

While wc, whoami, and ls are standard shell commands, put is typically a command used specifically within FTP clients rather than a standalone UNIX shell command.

The fork() system call creates a new child process by duplicating the calling parent process.

The $PATH environment variable holds a colon-separated list of directories that the shell searches for executable files when a command is entered.

The /etc directory in Linux contains all system-wide configuration files, including the /etc/passwd and /etc/shadow files for user authentication.

EXT3 (Third Extended Filesystem) is a native file system specifically designed and widely used for Linux partitions.

The chmod -R a+x progs command recursively (-R) adds (+) execute (x) permissions for all (a) users to the 'progs' directory and its contents.

UNIX fundamentally provides three file permissions: Read, Write, and Execute. These can be modified using the chmod command.

Windows CreateProcess() corresponds functionally to the UNIX fork() and exec(), WaitForSingleObject() maps to wait(), ReadFile() to read(), and CloseHandle() to close().

The nice command executes a program with a specified scheduling priority, effectively setting the task priority in UNIX.

The JMP (unconditional jump) instruction changes the instruction pointer but does not perform an arithmetic or logical operation, so no status flags are affected.

The Kernel is the core component of the operating system that resides between the hardware and the system call interface, managing system resources.

Linux fundamentally uses a Completely Fair Scheduler (CFS), which is a type of fair preemptive scheduling to allocate CPU time to processes.

In standard UNIX shells, the test command uses the = operator to compare strings for equality, though -eq is sometimes incorrectly conflated with string comparison despite being strictly for integers.

The UNIX file system utilizes a hierarchical directory structure, organizing files and directories into a tree-like hierarchy starting from the root (/).