Question 1

Web service processes on Linux: What is the name of the daemon (service process) commonly used by the Apache web server on UNIX/Linux systems?

Accepted Answer

Introduction / Context: The Apache HTTP Server is one of the most widely deployed web servers. On UNIX/Linux, it runs as a daemon process that listens on TCP port 80 (HTTP) and optionally 443 (HTTPS). Recognizing its service name is essential for starting, stopping, and troubleshooting web services. Given Data / Assumptions: An Apache installation is present on a UNIX-like system. Service management may be via systemd (systemctl) or legacy init scripts (service). The conventional daemon name is used. Concept / Approach: The Apache daemon is traditionally named httpd (HTTP daemon). Distributions package it under names like httpd (RHEL/CentOS) or apache2 (Debian/Ubuntu), but the underlying process binary is typically httpd. Administrators manage it with systemctl start httpd or service httpd start, depending on the init system. Step-by-Step Solution: Install the Apache package provided by your distribution.Start the daemon (for example, systemctl start httpd) and enable it to start on boot.Verify the process with ps aux | grep httpd or pgrep httpd.Open the default site in a browser (http://localhost/) to confirm it is serving content.Configure virtual hosts and TLS certificates as needed. Verification / Alternative check: Check listening sockets with ss -lntp | grep :80 or journalctl -u httpd for logs and errors. Confirm firewall rules allow inbound HTTP/HTTPS traffic. Why Other Options Are Wrong: a: apached is not the standard daemon name. c: html is a document format, not a daemon. d: shttp is not the default Apache service name. e: Not applicable since httpd is correct. Common Pitfalls: Confusing package names with service names (apache2 vs httpd), ignoring SELinux contexts on content directories, and forgetting to open ports 80/443 in the firewall. Final Answer: httpd

Question 2

UNIX permissions refresher: The symbolic-mode equivalent of chmod 761 letter sets user, group, and other permissions. Which mapping expresses that setting correctly?

Accepted Answer

Introduction / Context: File permissions in UNIX can be specified numerically (octal) or symbolically. Understanding the mapping between octal digits and read/write/execute bits helps you interpret and apply correct access controls quickly and accurately. Given Data / Assumptions: The numeric mode is 761, applied to a file named letter. Permission digits are ordered user (owner), group, and other. Each octal digit encodes r=4, w=2, x=1. Concept / Approach: The octal mode 761 translates as: user 7 (4+2+1 = rwx), group 6 (4+2 = rw-), other 1 (001 = --x). Symbolic mode expresses the same as u=rwx, g=rw, o=x. Either style yields the same permission bits when applied with chmod. Step-by-Step Solution: Break 761 into digits: 7, 6, 1 for user, group, other.Map each digit to permissions: 7 -> rwx, 6 -> rw-, 1 -> --x.Form symbolic expression: u=rwx, g=rw, o=x.Apply with chmod u=rwx,g=rw,o=x letter to set the bits.Confirm with ls -l letter to see -rwxrw--x for a regular file. Verification / Alternative check: Use stat -c %A letter to view human-readable permissions and stat -c %a letter to confirm numeric mode 761 after the change. Why Other Options Are Wrong: a: The syntax chmod 4=7, g=6, o=1 is invalid and mixes numbers erroneously. b: a=761 is not a valid symbolic-mode assignment; numeric modes are applied without a=. d: 167 reorders the bits incorrectly; the intended value is 761. e: Not applicable because the correct symbolic mapping is u=rwx, g=rw, o=x. Common Pitfalls: Confusing the order of user/group/other, misapplying execute bits on regular files, and forgetting that directories need x for traversal. Symbolic modes can add (+) or remove (-) bits for incremental changes. Final Answer: chmod u = rwx, g = rw, o = x letter

Question 3

Printing on UNIX systems: Which command submits a file to the System V–style print spooler for printing?

Accepted Answer

Introduction / Context: UNIX systems traditionally use print spoolers to queue and manage print jobs. Two major families exist: System V (lp, lpstat, cancel) and BSD (lpr, lpq, lprm, lpc). Recognizing the correct submit command for your platform is vital in mixed environments and exams. Given Data / Assumptions: The question targets the System V command set. A functioning print spooler and default destination are assumed. Basic printing to a local or network printer is intended. Concept / Approach: System V printing uses lp to send a file to the queue. Options select destination printers, copies, and banner pages. The BSD toolset uses lpr for submission. Many modern systems provide compatibility layers so both sets work, but the native System V submit command remains lp. Step-by-Step Solution: Submit a file: lp document.txtChoose a printer: lp -d printer_name document.txtSet copies: lp -n 2 document.txtCheck queue status: lpstat -oCancel a job: cancel job_id Verification / Alternative check: Confirm printing with lpstat and by checking the printer output. On systems with both toolsets, verify which backend (CUPS) interprets lp commands and how it maps to printers. Why Other Options Are Wrong: b: pg is a pager for viewing files page-by-page on screen, not printing. c, d: prn and print are DOS/Windows commands, not standard UNIX. e: Not applicable because lp is correct in System V environments. Common Pitfalls: Submitting to the wrong default destination, forgetting to specify copies or duplex options, and overlooking that CUPS may unify lp and lpr behavior with different defaults. Always check lpoptions -p printer -l for supported features. Final Answer: lp

Question 4

Print queue inspection (BSD family): Which command displays the current jobs in the print queue when using the BSD-style printing commands?

Accepted Answer

Introduction / Context: BSD-style printing utilities remain widely used, often via CUPS compatibility. Knowing which command lists queued print jobs helps diagnose stuck printouts, confirm submission, and manage priorities in multi-user environments. Given Data / Assumptions: The printing toolchain is the BSD set (lpr, lpq, lprm, lpc). A print queue and at least one printer are configured. The user needs to view queued jobs. Concept / Approach: In the BSD family, lpr submits print jobs, lpq displays the queue, lprm removes jobs, and lpc administers printing system parameters. On modern systems with CUPS, these commands map to the CUPS backend but retain their traditional roles. Step-by-Step Solution: Submit a job: lpr file.txtView queue: lpq or lpq -P printer_nameRemove a job: lprm job_idAdminister queues: lpc status, lpc stop/start printerMonitor: watch -n 2 lpq to refresh periodically Verification / Alternative check: Compare lpq output with the printer’s front panel or web UI. Also use lpstat (System V/CUPS) as an alternative if available. Why Other Options Are Wrong: b: lpr submits a job; it does not list queued jobs. c: lprm removes jobs from the queue. d: lpc handles administrative control and status, not simple queue listings in user workflows. e: Not applicable because lpq is the correct queue viewer in the BSD set. Common Pitfalls: Looking at the wrong printer’s queue in multi-printer setups; forgetting default printer selection; and interpreting CUPS mappings incorrectly when troubleshooting legacy scripts. Final Answer: lpq

Question 5

Working directory awareness: Which command prints the absolute path of your current working directory in a UNIX/Linux shell?

Accepted Answer

Introduction / Context: Navigating the filesystem efficiently requires awareness of your current directory. The pwd utility echoes the absolute path to the directory the shell considers current, which is critical when scripting, troubleshooting permissions, or composing relative paths. Given Data / Assumptions: A POSIX-compliant shell environment is in use. The goal is to display the present working directory path. No need to alter environment variables or prompt settings. Concept / Approach: pwd expands any symbolic links based on implementation or options (for example, pwd -P for the physical directory). It reads from the shell’s notion of the current directory, which updates when cd is executed. This information is often embedded into shell prompts as well. Step-by-Step Solution: Open a shell and type pwd to print the current path.Change directory with cd /etc and run pwd again to verify.Use pwd -P to resolve symlinks to the physical path if needed.Embed in scripts for logging: echo "Running from $(pwd)".Customize PS1 to show \w (Bash) for the working directory in prompts. Verification / Alternative check: Cross-check with ls to list directory contents, confirming you are where you expect. Use realpath . for an explicit physical path. Why Other Options Are Wrong: a: path is a DOS command for executable search path; not a UNIX directory query. c: prompt $p$g is a DOS prompt customization, irrelevant in UNIX. d: dir lists directory contents (DOS/also an alias to ls on some systems) but does not print the current path like pwd. e: Not applicable because pwd is correct. Common Pitfalls: Confusing logical vs physical paths when symlinks are involved; using cd -P and pwd -P to avoid ambiguity in scripts that rely on actual filesystem paths. Final Answer: pwd

Question 6

Storage usage overview: Which command summarizes disk usage for files and directories (for example, showing total space consumed by each subdirectory)?

Accepted Answer

Introduction / Context: Understanding how storage is consumed on a server or workstation helps with capacity planning and cleanup. The du utility reports the amount of disk space used by files and directories, optionally aggregating totals at each directory level. Given Data / Assumptions: A POSIX system with standard userland tools is available. You want a summary per directory or a grand total. Human-readable sizes are preferred for quick interpretation. Concept / Approach: du traverses directories and sums allocated blocks. Useful flags include -h for human-readable units, -s for summary (do not descend), and -x to stay on one filesystem. Pair du with sort -h to identify the largest disk consumers quickly. Step-by-Step Solution: Show per-directory usage: du -h .Summarize only the current directory: du -sh .Find top consumers: du -h --max-depth=1 | sort -hLimit to one filesystem: du -xh / | sort -h | tailAutomate cleanup decisions by reviewing the largest paths. Verification / Alternative check: Use df -h to verify overall filesystem free/used space. Compare du results before and after deleting large logs or caches to confirm reclaimed space. Note that sparse files and copy-on-write filesystems may complicate exact interpretations. Why Other Options Are Wrong: a: disk is not a standard UNIX command for usage summarization. c: fdisk edits partition tables; it does not report per-directory usage. d: chkdsk is a DOS/Windows filesystem checker, not a UNIX usage tool. e: Not applicable because du is correct. Common Pitfalls: Running du on mount points with slow or remote filesystems, misinterpreting sizes when hard links or snapshots are present, and forgetting -x when you want to avoid descending into other mounted filesystems. Final Answer: du

Question 7

Linux security administration  On a Linux system, which tool can be used to configure a packet-filtering firewall on legacy kernels (prior to iptables/nftables)?

Accepted Answer

Introduction / Context: A firewall on Linux controls inbound and outbound network traffic by filtering packets based on rules. Over the years, Linux has offered several frameworks: ipfwadm (very old), ipchains (Linux 2.2 era), iptables (Linux 2.4+), and modern nftables. Understanding which command configures which framework is essential for system administration, historical troubleshooting, and certification exams. Given Data / Assumptions: The question refers to “set up a firewall” on legacy Linux systems. Options include various networking tools and one known firewall utility. Context implies pre-iptables kernels where ipchains was standard. Concept / Approach: In legacy (Linux 2.2) systems, ipchains managed rules for packet filtering and Network Address Translation. It predates iptables (netfilter in Linux 2.4) and nftables (newer kernels). Tools like netstat and route report or adjust sockets and routing tables, but they do not create filtering rules. Therefore, choosing the firewall-specific utility is the correct approach. Step-by-Step Solution: Identify which option is a firewall rule manager: ipchains.Exclude reporting/config tools that are not firewalls (netstat, route).Exclude unrelated commands (trace is not a standard Linux firewall tool).Select ipchains as the correct historical firewall configuration command. Verification / Alternative check: On legacy systems: running ipchains -L lists chain rules. On newer systems, iptables or nftables are used instead, confirming the historical nature of ipchains. Why Other Options Are Wrong: netstat: displays sockets, routing, and interface statistics; it does not filter traffic.route: edits the kernel routing table; not a firewall.trace: not a standard Linux firewall utility; possibly confuses with traceroute. Common Pitfalls: Mixing up ipchains with iptables/nftables across kernel versions. Assuming route changes secure a system; routing and filtering are separate. Forgetting to persist firewall rules across reboots with appropriate scripts. Final Answer: ipchains

Question 8

Network Information Service (NIS) basics  Which NIS client command returns the name of the NIS server currently serving the client system?

Accepted Answer

Introduction / Context: Network Information Service (NIS), formerly known as Yellow Pages (YP), centralizes user, group, and other administrative maps. Troubleshooting NIS often requires confirming which server the client is bound to. Several commands exist, each with a distinct purpose, and knowing which one reveals the current server is fundamental. Given Data / Assumptions: NIS client utilities are installed. The client is already bound to an NIS server (via ypbind or system services). We want the command that shows the serving NIS master or current server. Concept / Approach: The ypwhich command queries the local binding and prints the hostname of the NIS server that the client is currently using. Other commands have different roles: ypbind manages binding; ypcat prints the contents of a map; yppoll queries a map's order number and master but is not primarily used to display the bound server for the client itself. Step-by-Step Solution: Identify the task: display the current NIS server.Match functionality: ypwhich reports the NIS server.Exclude tools with different purposes (binding, map content, map order).Select ypwhich. Verification / Alternative check: Run ypwhich; it should output the NIS server hostname. Running ypwhich -m lists NIS maps and their masters, reinforcing understanding of the toolset. Why Other Options Are Wrong: ypbind: daemon that binds the client to a server; not a query tool.ypcat: prints map contents; does not show the bound server.yppoll: checks map order/master for a given map; not the general “who am I bound to” tool. Common Pitfalls: Confusing ypwhich -m (map masters) with the basic ypwhich server query. Forgetting that NIS may be firewalled; ensure ports are open for binding and queries. Assuming DNS and NIS are the same; they serve different purposes. Final Answer: ypwhich

Question 9

Linux routing configuration  On a Linux router or host, which command is used to add, delete, or view entries in the kernel routing table?

Accepted Answer

Introduction / Context: Routing determines where IP packets are forwarded. On classic Linux systems, administrators use user-space tools to interact with the kernel's routing table. Although modern distributions prefer the ip command from iproute2, many legacy systems and exam questions reference the older route tool. Given Data / Assumptions: We need the command traditionally used to add routes. System runs a standard Linux environment. We differentiate between viewing statistics and manipulating routes. Concept / Approach: The route command (now largely superseded by ip route) can add, delete, and display routes in the kernel routing table. Tools like netstat display network statistics and routes but are not typically used to add new routes. Nonstandard names like addroute or net do not represent the canonical Linux tools for this task. Step-by-Step Solution: Identify legacy command used to modify routes: route.Exclude report-only tools such as netstat.Exclude nonexistent or platform-specific aliases (addroute, net).Select route as the correct answer. Verification / Alternative check: Modern equivalent is ip route add or ip route show. Testing with either tool verifies route manipulation concepts are consistent. Why Other Options Are Wrong: addroute: not a standard Linux command.netstat: reports statistics and can display routes but does not add them.net: ambiguous/nonstandard in Linux for routing tasks. Common Pitfalls: Forgetting persistence; add routes permanently via network scripts or systemd-networkd. Adding host routes when a default route is intended. Not updating firewall rules to permit forwarding when acting as a router. Final Answer: route

Question 10

UNIX/Linux file permissions  Which single chmod command assigns read-only permission to all three classes (user, group, and others) for a file named 'letter'?

Accepted Answer

Introduction / Context: UNIX/Linux permissions protect files by specifying what actions each class of user can perform: read, write, and execute for user (u), group (g), and others (o). The chmod command modifies these bits either symbolically or numerically, and it is common to grant uniform read-only access to all classes for shared documents. Given Data / Assumptions: Target file name: letter. Goal: read-only for user, group, and others. Single command preferred, using symbolic mode. Concept / Approach: Read-only means setting read and clearing write and execute for u, g, and o. Using symbolic mode, chmod ugo=r letter sets exactly the read bit for all classes at once. Alternatives either fail to remove existing write/execute bits or do not set all classes correctly. Step-by-Step Solution: Desired permissions: r-- r-- r-- (octal 444).Symbolic equivalent: ugo=r.Apply: chmod ugo = r letter.Confirm with ls -l to see -r--r--r-- for the file. Verification / Alternative check: Octal mode provides a quick check: chmod 444 letter yields the same result as ugo=r. Verifying with ls -l ensures correct application. Why Other Options Are Wrong: Option A only adds read for u and g and removes execute for o, leaving other bits unchanged.Option C removes read and write for all (a-rw) and leaves execute unchanged; not read-only.Option D adds read for g and o only, leaving user and other bits undefined. Common Pitfalls: Using + instead of =, which can leave unwanted write or execute bits set. Forgetting to include all classes (ugo) when uniform permissions are required. Confusing octal and symbolic modes. Final Answer: chmod ugo = r letter

Question 11

Linux process control  Which command is used to terminate (send a signal to) a running process by Process ID (PID) or by name?

Accepted Answer

Introduction / Context: Process management is a core skill in Linux administration. Sometimes a process misbehaves or must be stopped for maintenance. Linux uses signals to control processes, and the standard command to send these signals is kill (and its variants). Understanding how and when to use kill is essential for safe system operation. Given Data / Assumptions: You have a target process identified by PID or name. You need to terminate, interrupt, or otherwise signal that process. Standard userland tools are available. Concept / Approach: The kill command sends a signal to a process. By default it sends SIGTERM (15), requesting graceful termination. If the process does not exit, SIGKILL (9) can be used to force termination. Utilities like killall or pkill target processes by name, but they are wrappers around the same signaling mechanism. Step-by-Step Solution: Find the PID via ps, pgrep, or top.Attempt graceful stop: kill (SIGTERM).If needed, force stop: kill -9 (SIGKILL).For name-based: pkill or killall (distribution dependent). Verification / Alternative check: Confirm with ps or pgrep that the process has exited. Review logs if a service manager (systemd) restarts it automatically; in that case, use systemctl stop for managed services. Why Other Options Are Wrong: cancel: not a standard Linux process signaling command.haltsys and shutdown: control system power state, not individual processes. Common Pitfalls: Using SIGKILL prematurely, which prevents cleanup handlers from running. Forgetting that services supervised by systemd may respawn after kill. Signaling the wrong PID; always double-check with ps/top. Final Answer: kill

Question 12

vi text editor operations  In the vi editor, which command deletes three words forward from the cursor position (treating punctuation and whitespace by vi's word rules)?

Accepted Answer

Introduction / Context: The vi editor (and its improved version, Vim) is ubiquitous on UNIX/Linux. Efficient editing depends on mastering operator + motion combinations. Deleting multiple words in one keystroke is a common task that highlights how counts and motions work together in vi's modal editing model. Given Data / Assumptions: We are in Normal mode (command mode) in vi. We wish to delete a span defined by a word motion. We need exactly three words removed starting at the cursor. Concept / Approach: In vi, d is the delete operator and w is the word motion (move to the start of the next word). Prefixing with a count multiplies the motion. Thus, 3dw or d3w deletes three words forward. The option shown as “3 dw” represents this combined form with a count of 3 applied to dw. Step-by-Step Solution: Determine the operator: d (delete).Determine the motion: w (word forward).Apply a count of 3: 3dw (equivalently d3w).Result: three words ahead of the cursor are removed and stored in a register. Verification / Alternative check: Try variants such as d3w, which performs the same action. For whole words including trailing space behavior, 3de or 3dW can be compared to understand the difference between word and WORD motions. Why Other Options Are Wrong: 3$d: deletes from cursor to the end of line, not three words.3 x: deletes three characters, not words.3 dd: deletes three lines, not words. Common Pitfalls: Confusing word motions (w, e, b) with line motions (j, k, 0, $). Using Uppercase W which treats non-space punctuation differently. Not being in Normal mode; commands fail or insert text in Insert mode. Final Answer: 3 dw

Question 13

Linux partition type codes (MBR)  In fdisk with Master Boot Record (MBR) partitioning, which hexadecimal codes designate a Linux swap partition and a Linux native (filesystem) partition, respectively?

Accepted Answer

Introduction / Context: On MBR-partitioned disks, fdisk assigns a one-byte hexadecimal type to each partition. Correctly labeling partitions ensures the operating system recognizes their intended use, such as swap or a Linux filesystem. Although GPT now uses GUIDs, many legacy systems and exams still reference these classic MBR codes. Given Data / Assumptions: Using MBR (not GPT). Creating Linux swap and Linux native filesystem partitions. Need to recall the correct hex identifiers. Concept / Approach: The standard codes are: 0x82 = Linux swap and 0x83 = Linux native filesystem (for ext2/3/4, xfs when using MBR). Setting these correctly helps tools like the initramfs, swapon, and mount identify partitions at boot. Step-by-Step Solution: Create partitions with fdisk.Use the “t” command to set types: enter 82 for swap and 83 for native.Format swap via mkswap and filesystems via mkfs.ext4 or similar.Add entries to /etc/fstab for persistence and test with swapon --show and findmnt. Verification / Alternative check: Use blkid to confirm types and UUIDs. lsblk -f also displays filesystem and mount information for quick verification. Why Other Options Are Wrong: 92/93 and 63/64: not standard Linux swap/native MBR codes.82 and 85: 85 is typically Linux extended partition on some tools, not Linux native filesystem. Common Pitfalls: Forgetting to run mkswap after labeling a partition as swap. Using device names instead of UUIDs in /etc/fstab, risking renumbering issues. Confusing MBR codes with GPT partition type GUIDs. Final Answer: 82 and 83

Question 14

Sorting text on UNIX/Linux  Which command sorts the lines of a file in reverse (descending) order when run from the shell?

Accepted Answer

Introduction / Context: Sorting text files is a routine administrative task. The standard utility on UNIX/Linux is sort, which supports many options for collation, numeric comparison, and order direction. Knowing the correct flag for reverse order prevents manual post-processing and simplifies pipelines. Given Data / Assumptions: We want reverse (descending) order. We will use the standard command-line tool set. Default collation is acceptable unless otherwise specified. Concept / Approach: The sort utility orders input lines. By default it sorts ascending. The option -r reverses the result, producing descending order. Other flags such as -n (numeric) or -k (key) can be combined depending on the data set. Step-by-Step Solution: Use ascending by default: sort file.txt.Add reverse flag: sort -r file.txt for descending order.Combine with numeric if needed: sort -nr file.txt for descending numeric sort.Integrate into pipelines: cat file.txt | sort -r > out.txt. Verification / Alternative check: Test with a known sequence (e.g., 1, 2, 3) and confirm output (3, 2, 1). Use LC_ALL=C to provide bytewise collation for reproducibility in scripts. Why Other Options Are Wrong: st and sh are unrelated; sh invokes a shell, not sorting.sort (without -r) sorts ascending; not reverse order. Common Pitfalls: Forgetting -n for numeric data, which causes 100 to sort before 20 lexically. Not setting locale when deterministic order is required across systems. Sorting by the wrong key when dealing with multi-column data; use -k properly. Final Answer: sort -r

Question 15

Free Software Foundation (FSF) history  Who founded the Free Software Foundation, the nonprofit organization that promotes computer user freedom and maintains the GNU project?

Accepted Answer

Introduction / Context: The Free Software Foundation (FSF) is central to the history of free and open-source software. Understanding its origins clarifies the distinction between GNU (a complete free operating system initiated by the FSF) and the Linux kernel, as well as the broader ecosystem that became GNU/Linux distributions. Given Data / Assumptions: The FSF is a nonprofit advocating for user freedoms: to run, study, share, and modify software. We identify the founder, not contributors or related figures. Key historical names include Richard Stallman and Linus Torvalds. Concept / Approach: Richard Stallman founded the FSF in 1985 and launched the GNU project, producing critical components like GCC, glibc, and coreutils. Linus Torvalds created the Linux kernel in 1991, which later combined with GNU to form GNU/Linux systems. Bob Young co-founded Red Hat but did not found the FSF. Step-by-Step Solution: Identify the founder of FSF: Richard Stallman.Differentiate from Linux kernel's creator (Linus Torvalds).Recognize Bob Young's role in commercial Linux distribution, not FSF founding.Select Richard Stallman. Verification / Alternative check: FSF public history and GNU project documentation consistently credit Richard Stallman as founder and long-time leader, confirming the answer. Why Other Options Are Wrong: Linus Torvalds: created the Linux kernel; not FSF founder.Bob Young: co-founded Red Hat; not FSF founder.All of the above: incorrect because only one person founded FSF. Common Pitfalls: Conflating GNU and Linux; GNU is userland and tools, Linux is the kernel. Assuming corporate founders are behind nonprofit foundations. Equating open-source with free software; FSF emphasizes freedom, not just openness. Final Answer: Richard Stallman

Question 16

Partition table formats on PCs  Historically, which partition table format has Linux commonly used on IBM-PC compatible systems for disk partitioning (prior to widespread GPT adoption)?

Accepted Answer

Introduction / Context: Disk partitioning on IBM-PC compatible systems historically relied on the Master Boot Record (MBR) scheme, often referred to as the DOS partition table. While modern systems favor the GUID Partition Table (GPT), Linux has long supported and commonly used DOS/MBR due to broad firmware and tool compatibility. Given Data / Assumptions: The question targets historical/common use on PC hardware. We are choosing among named formats, not filesystems. Linux supports many schemes, but one was standard for decades. Concept / Approach: The DOS partition table (MBR) organizes up to four primary partitions (or three primary plus one extended containing logical partitions). Tools like fdisk, cfdisk, and sfdisk manage MBR layouts. Although BSD and UnixWare have their own disklabel or VTOC formats, they were not the default standard on typical PC installs of Linux. Step-by-Step Solution: Identify the widely used PC partition format prior to GPT: DOS/MBR.Recognize Linux's broad support and installer defaults for DOS/MBR for many years.Exclude vendor-specific or platform-specific formats (BSD disklabel, UnixWare VTOC).Select DOS as the correct answer. Verification / Alternative check: Review man pages for fdisk and legacy installer docs; they defaulted to MBR for BIOS systems. On UEFI hardware, GPT is now prevalent, but the question focuses on historical/common usage. Why Other Options Are Wrong: Linux: not a partition table format; it is an operating system kernel.BSD and UnixWare: platform-specific schemes not commonly used by default on Linux PCs. Common Pitfalls: Confusing partition tables (MBR/GPT) with filesystems (ext4, xfs, etc.). Assuming UEFI/GPT has always been the standard; GPT adoption is relatively recent. Believing the answer is filesystem-related due to the word “Linux.” Final Answer: DOS

Question 17

Linux desktop frameworks: GNOME was historically architected around which middleware/component model for inter-process communication and object services?

Accepted Answer

Introduction / Context: GNOME is a popular desktop environment for UNIX/Linux systems. Early versions of GNOME used a specific middleware approach to enable inter-process communication, component interaction, and service discovery between applications. Understanding this historical design choice clarifies why certain libraries and daemons appeared in classic GNOME stacks. Given Data / Assumptions: The question asks which component model GNOME was based on historically. We consider the early GNOME architecture (GNOME 1.x/2.x era). Terminology like CORBA and COM/DCOM refers to industry component frameworks. Concept / Approach: Classic GNOME used CORBA (Common Object Request Broker Architecture) via the lightweight ORBit implementation. CORBA defined an interface-based, language-neutral way for distributed objects to communicate. GNOME used CORBA/ORBit and tools like Bonobo for component embedding and IPC before later transitioning toward D-Bus and newer technologies. Step-by-Step Solution: Identify historical GNOME IPC/component framework → CORBA (with ORBit and Bonobo).Contrast with Microsoft COM/DCOM and OLE DB, which are Windows-centric and not native to GNOME.Select the option that matches GNOME’s historical basis: CORBA toolkit. Verification / Alternative check: Check legacy GNOME documentation mentioning ORBit, Bonobo, and CORBA IDL definitions used for component interaction. Modern GNOME uses different IPC (e.g., D-Bus), but the question targets the historical foundation. Why Other Options Are Wrong: COM/DCOM toolkit: Microsoft technology, not used by GNOME. ORE toolkit: Not a GNOME component model. OLE DB toolkit: Microsoft data access API, unrelated to GNOME IPC. None of the above: Incorrect because CORBA is correct. Common Pitfalls: Confusing current GNOME IPC (D-Bus) with the historic CORBA/Bonobo era; assuming Windows component models apply to GNOME. Final Answer: CORBA toolkit

Question 18

UNIX/Linux basics: Which single command is used to copy a file (source to destination) on the same system?

Accepted Answer

Introduction / Context: Copying files is a fundamental UNIX/Linux task. While several utilities can archive or stream data, only one standard command is used for straightforward file-to-file copying within the filesystem. Given Data / Assumptions: You need to copy a local file to another path on the same machine. Standard POSIX utilities are available. No special archiving or backup behavior is required. Concept / Approach: The cp command copies files and directories. Typical usage is cp source destination or cp -r src_dir dst_dir for directories. Other tools like tar and cpio create archives or stream file trees; they are overkill for a simple copy. The command copy is DOS/Windows syntax, not POSIX. Step-by-Step Solution: Basic file copy: cp file1.txt file2.txtCopy to directory: cp file1.txt /path/to/dir/Recursive copy: cp -r dirA dirBPreserve attributes (GNU): cp -a src/ dst/ Verification / Alternative check: Run ls -l on the destination to confirm the file exists and has expected size and permissions. For integrity, compare checksums with sha256sum source destination. Why Other Options Are Wrong: tar, cpio: Archiving/streaming tools, not simple copy commands. copy: DOS/Windows command, not standard on UNIX/Linux. None of the above: Incorrect because cp is correct. Common Pitfalls: Forgetting -r when copying directories; accidentally overwriting existing files (use -i to prompt); losing attributes (use -a when needed). Final Answer: cp

Question 19

File permissions in UNIX: Which chmod command adds executable permission for the owner of the file named 'letter' (without altering group or others)?

Accepted Answer

Introduction / Context: UNIX permissions control who can read, write, or execute files. The chmod command modifies these permissions for the owner (u), group (g), and others (o). Knowing precise symbolic modes is essential when granting just the needed rights. Given Data / Assumptions: Target file: letter. Goal: add execute permission for the owner only. No changes should be made to group or others. Concept / Approach: Symbolic mode in chmod uses entity (u, g, o, a), operator (+, -, =), and permission (r, w, x). To add execute permission for owner only, use chmod u+x letter. This augments existing permissions rather than replacing them. Step-by-Step Solution: Identify entity: owner → uOperation: add → +Permission: execute → xCommand: chmod u+x letter Verification / Alternative check: List permissions with ls -l letter before and after; the first field’s owner triad should gain x (e.g., from rw- to rwx). Why Other Options Are Wrong: chmod ugo+x: Grants execute to everyone (owner, group, others). chmod u+w: Adds write, not execute. chmod g+x: Changes group, not owner. None of the above: Incorrect because chmod u+x letter is right. Common Pitfalls: Using = which replaces permissions entirely; accidentally granting execute to all users; forgetting that scripts also may need a valid shebang and executable bit. Final Answer: chmod u+x letter

Question 20

UNIX utilities: Which command compares two files byte-by-byte and reports the first difference (primarily for binary comparison)?

Accepted Answer

Introduction / Context: Comparing files is common in troubleshooting, backups, and build pipelines. UNIX provides multiple tools for comparison; choosing the right one depends on whether you need binary or textual diffs. Given Data / Assumptions: You need to know if two files are identical at the byte level. Output should indicate the first differing location for quick diagnostics. Standard UNIX tools are available. Concept / Approach: The cmp command compares two files byte by byte and reports the first mismatch (with offsets). This is ideal for binary equivalence checks. For textual differences line by line, diff is typically used, but diff is not listed here. The du command reports disk usage. DOS comp is not a standard UNIX tool. Step-by-Step Solution: Run cmp file1 file2If silent success is desired, use cmp -s file1 file2 and check exit status.Automate equivalence tests in scripts by checking the return code (0 = identical, non-zero = different). Verification / Alternative check: Use checksums: sha256sum file1 file2 and compare hashes; identical hashes imply identical content. Why Other Options Are Wrong: ccp: Not a standard UNIX comparison command. du: Reports disk usage, not content differences. comp: DOS/Windows utility, not standard on UNIX. None of the above: Incorrect because cmp is correct. Common Pitfalls: Expecting human-readable line diffs from cmp; for that, use diff. Comparing text files with different line endings may show differences; normalize if appropriate. Final Answer: cmp

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