Free 010-200 practice test: 30 questions with answers

The two dots refer to the parent directory, so cd .. moves one level up from assets to site. cd /srv jumps to an unrelated absolute path, cd ~ returns to the home directory, and cd ../.. goes two levels up to /srv/www.

Section 5 of the manual describes file formats and conventions, and passwd(5) documents the fields of /etc/passwd. Section 1 covers the passwd command, section 8 covers system administration commands such as useradd, and man -k searches page descriptions rather than showing a page.

apropos searches the names and short descriptions in the manual index for a keyword, the same as man -k. whereis locates binaries, sources and man pages by file name, which requires knowing the name, and type shows how the shell interprets a name.

rm -r removes a directory together with everything beneath it. rmdir only removes empty directories, plain rm refuses to remove a directory without -r, and mv only relocates the tree without deleting it.

mv changes a file's name without copying its data, so the old name disappears. cp duplicates the data, ln adds a second name to the same file while the original name remains, and touch creates an empty file or updates timestamps.

Tab completion fills in a unique match and lists candidates when several names share the typed prefix. Rerunning history is done with the Up arrow or !!, Ctrl+A moves to the start of the line, and Ctrl+D ends input at an empty prompt, so those statements describe other keys.

-c creates an archive, -z compresses it with gzip and -f names the archive file. The other options extract (-x), decompress with gzip -d, or list (-t) the contents instead of creating an archive.

>> appends standard output to the end of the file and creates the file if it is missing. > replaces existing contents, < feeds input from a file, and 2> redirects standard error rather than standard output.

grep -c prints the number of lines that match the pattern. grep -v prints the lines that do not match, wc -c counts bytes rather than matching lines, and sort -u sorts unique lines without counting matches.

The shebang is the two characters #! followed by the absolute path to the interpreter, and the kernel uses it to launch the script. The other lines lack the #! characters or a valid absolute interpreter path, so the kernel will not start Bash.

u+x adds the execute permission for the owner, which lets the shell run the script by path. Mode 600 gives only read and write, chown changes ownership, and u-w removes write permission, so none of them add execute permission.

-c creates, -x extracts and -t lists the archive contents without extracting them. tar does not compress unless a compression option is given, and it does not remove the source files after archiving them.

SIGKILL (9) cannot be caught, blocked or ignored, so the kernel ends the process directly. SIGTERM, SIGHUP and SIGINT can be caught or ignored by a program, which is why they are tried before SIGKILL.

Nice values range from -20 (highest priority) to 19 (lowest), so a positive adjustment makes the scheduler give the job less CPU. A negative value raises priority, SIGKILL ends the job, and fg only moves a job to the foreground without changing its priority.

journalctl reads the journal that systemd collects, and options such as -u filter it by unit. lsblk lists block devices, crontab -l lists scheduled cron jobs, and hostnamectl shows or sets the host name settings.

lsblk lists block devices such as disks and their partitions, with names and mount points. lsmod lists loaded kernel modules, lspci lists PCI hardware, and lsattr shows file attributes on filesystems that support them.

/etc/hosts maps host names to IP addresses locally, so those names resolve without a DNS query. /etc/resolv.conf names DNS servers, /etc/fstab lists filesystems to mount, and /etc/passwd stores user account records.

MBR's 32-bit sector addressing cannot reach the end of very large disks, while GPT uses 64-bit addresses. MBR does not have unlimited capacity, GPT still needs a boot loader, and GPT is not restricted to systems without a BIOS.

The GPL is a copyleft license, so a distributed modified work must make its source available under GPL terms. Charging a fee and distributing the program are both allowed under the GPL, and the license does not require replacing the library with proprietary code.

Debian and Ubuntu use apt, a front end to the dpkg package system. Red Hat-based systems use rpm and dnf, Arch uses pacman, and SUSE uses zypper, so those options name the wrong distribution family.

Ubuntu is built on Debian and uses the deb package format with apt and dpkg. Red Hat Enterprise Linux uses rpm, Slackware uses tarball packages, and Arch Linux uses pacman, so none of them is the base of Ubuntu.

The GPL source-offer obligation is triggered by distributing copies to others. Private internal use of a modified version does not require publishing it. The GPL sets no 30-day publication rule, needs no author approval, and does not require relicensing.

Apache HTTP Server and Samba are open source server programs commonly deployed on Linux. InDesign and GIMP are desktop applications, and Exchange is a proprietary Microsoft server product.

The MIT License is permissive: it allows proprietary derivative works and mainly requires the copyright notice and license text to be kept. The GPL versions and the Affero license are copyleft licenses that require derivative works distributed to others to remain open under compatible terms.

Mode 644 gives the owner read and write (6), and the group and others read (4). Mode 600 denies the group and others any access, 664 gives the group write permission, and 755 gives execute permission to everyone.

sudo runs one command as root after the user authenticates with their own password, and the action is logged. su switches accounts using the target account's password, passwd changes passwords, and visudo edits the sudoers configuration.

scp copies files over an SSH connection, so the data is encrypted in transit. cp only works on the local system, ftp sends data without encryption by default, and tar builds archives without transferring them.

/etc/shadow holds password hashes and password aging data, and it is normally readable only by root. /etc/passwd holds account fields that ordinary users can read, /etc/group lists groups and members, and /etc/hosts maps names to addresses.

The sticky bit on a directory, as used on /tmp, lets only the file owner, the directory owner or root delete or rename entries there. The setuid bit is meant for executables, setgid controls group inheritance, and mode 777 without a special bit lets any user delete any file.

chown -R changes the owner of the directory and of every file and subdirectory beneath it. chmod -R 777 opens permissions to everyone without changing ownership, a glob-based chown misses nested contents, and the setuid bit on a directory does not change its owner.