LPIC-1 Shells, Scripting and Data Management Practice Test 2 — 15 Questions

Question 1

A script uses a while loop to read lines from a file, but a variable set inside the loop is empty after the loop finishes. What is the most likely cause?

Accepted Answer

The while loop is part of a pipeline, causing it to run in a subshell.. When a while loop is part of a pipeline (e.g., `while read line; do ... done < file | command` or `command | while read line; do ... done`), each command in the pipeline runs in its own subshell. Variables set inside the subshell are not propagated back to the parent shell, so they appear empty after the loop finishes. This is a common pitfall in shell scripting.

Answer

The file has an empty line at the end.

Answer

The variable is declared as readonly.

Answer

The variable name contains spaces.

Question 2

Which sed command will replace the first occurrence of 'foo' with 'bar' on each line of a file?

Accepted Answer

sed 's/foo/bar/' file. The default behavior of the `s` (substitute) command in sed is to replace only the first occurrence of the pattern on each line. Without a numeric flag, `sed 's/foo/bar/' file` replaces the first 'foo' on each line with 'bar'. The `g` flag would replace all occurrences, not just the first.

Answer

sed 's/foo/bar/g' file

Answer

sed 's/foo/bar/0' file

Answer

sed 's/foo/bar/2' file

Question 3

Given a file with lines like 'John:23:Engineer', which awk command prints only the name and department (first and third fields) separated by a space?

Accepted Answer

awk -F: '{print $1,$3}' file. The `-F:` flag sets the field separator to colon, and `{print $1,$3}` prints the first and third fields separated by the default output field separator (a space). This matches the requirement to output the name and department from lines like 'John:23:Engineer'.

Answer

awk -F: '{print $1,$2}' file

Answer

awk -F: '{print $1 $3}' file

Answer

awk -F: '{print $1 $2}' file

Question 4

A script uses a here-document to pass multi-line input to a command. Which here-document syntax will prevent variable expansion inside the document?

Accepted Answer

<< 'EOF'. Single-quoting the delimiter (e.g., `<< 'EOF'`) prevents the shell from performing variable expansion and command substitution within the here-document. The shell treats the quoted delimiter literally, so all content between the start and end markers is passed verbatim to the command.

Answer

<< EOF

Answer

<<- EOF

Answer

<< "EOF"

Question 5

Which command combination will display a sorted list of unique lines from a file?

Accepted Answer

cat file | sort | uniq. (cat file | sort | uniq) is the only combination that always produces a sorted list of unique lines. The `sort` command first sorts all lines, making duplicates adjacent, then `uniq` removes those adjacent duplicates, guaranteeing a sorted unique output. Option A (cat file | uniq | sort) may omit non-adjacent duplicates, so it only works if the file is already sorted or duplicates happen to be adjacent. Option B (sort -u file) is a single command that also produces a sorted unique list, but the question specifically asks for a 'command combination' (i.e., a pipeline of multiple commands), so B is not a valid answer. Option D (Both A and C) is incorrect because A does not always work.

Answer

cat file | uniq | sort

Answer

sort -u file

Answer

Both A and C

Question 6

Which command returns the directory part of a full path like '/home/user/script.sh'?

Accepted Answer

dirname /home/user/script.sh. The `dirname` command extracts the directory portion of a full path, returning `/home/user` for the given example. Option B is correct because it directly answers the question—`dirname` is a standard command for this purpose. Option A uses incorrect syntax, Option C describes a parameter expansion (not a command), and Option D (`basename`) returns the filename, not the directory.

Answer

echo ${/home/user/script.sh%/*}

Answer

Either dirname or the expansion ${path%/*} if path is set to the full path

Answer

basename /home/user/script.sh

Question 7

A script reads a CSV file where fields may contain commas within quoted strings. Which approach correctly parses such fields?

Accepted Answer

Using awk or a dedicated tool like csvkit. CSV fields containing commas within quoted strings require a parser that understands CSV quoting rules. Awk can be scripted to handle quoted fields, and dedicated tools like csvkit (e.g., csvcut, csvformat) are designed specifically to parse CSV according to RFC 4180, correctly ignoring commas inside double-quoted strings.

Answer

Using 'cut -d',' -f1,2 file'

Answer

Using 'while IFS= read -r line; do ... done < file' and parsing manually

Answer

Using 'while IFS=',' read -r f1 f2; do ... done < file'

Question 8

Which TWO of the following are required for a bash script to be executed by the shell (assuming the script is in the current directory)?

Accepted Answer

The script must have a shebang (#!) as the first line.. The shebang (#!) as the first line of a bash script tells the kernel which interpreter to use (e.g., #!/bin/bash). Without it, the shell may attempt to execute the script using the default shell (often /bin/sh), which can lead to syntax errors or unexpected behavior. The shebang is essential for explicitly specifying the interpreter, especially when the script uses bash-specific features.

Answer

The script must not contain any comments.

Answer

The script must have a .sh extension.

Answer

The script must be in the PATH environment variable.

Question 9

Which THREE of the following commands can be used to transform delimited text (e.g., CSV) by selecting specific fields or columns?

Accepted Answer

cut. The `cut` command is specifically designed to extract sections from each line of input, making it ideal for selecting fields from delimited text like CSV. By using the `-d` option to specify a delimiter (e.g., `-d','`) and the `-f` option to choose fields (e.g., `-f1,3`), `cut` can efficiently extract columns without additional processing.

Answer

tr

Answer

cat

Question 10

Which TWO of the following are true about the 'source' command in bash?

Accepted Answer

It can be abbreviated as '.' (dot).. The 'source' command can be abbreviated as a single dot ('.') in bash and other POSIX-compliant shells. This dot notation is a standard feature defined by POSIX, and both forms execute the script in the current shell environment, not a subshell.

Answer

It executes a script in a subshell.

Answer

It is only available in bash and not in POSIX sh.

Answer

It requires the script to have execute permission.

Question 11

Refer to the exhibit. An administrator installed a new command in /opt/bin/ but cannot run it without specifying the full path. What is the likely cause?

Accepted Answer

The command is not in the PATH.. The administrator installed the command in /opt/bin/, but the shell cannot find it without the full path because /opt/bin/ is not listed in the PATH environment variable. The PATH variable defines the directories the shell searches for executable commands; if a directory is omitted, commands within it must be invoked with an absolute or relative path.

Answer

The command is an alias that conflicts.

Answer

The command has no execute permission.

Answer

The command is a function that overrides.

Question 12

Refer to the exhibit. What will be the output when this script is executed?

Accepted Answer

a b c
d e f. The script reads two lines from standard input. The first `read a b` reads the first line 'a b c'. Since there are three words but only two variables, the last variable `b` captures the remainder of the line, so a='a' and b='b c'. The second `read d e` reads the second line 'd e f', so d='d' and e='e f'. The `echo -e` command outputs the values with an escaped newline (`
`) between them, producing two lines: 'a b c' and 'd e f', represented as 'a b c
d e f'.

Answer

a b
d e

Answer

a b

Answer

The script will error because of incorrect read syntax.

Question 13

Refer to the exhibit. When will the cron job execute?

Accepted Answer

Every minute.. The cron job entry `* * * * *` specifies five fields (minute, hour, day of month, month, day of week), each set to `*`, meaning 'every'. This results in the job executing every minute of every hour, every day of the month, every month, and every day of the week — i.e., every minute without restriction.

Answer

Every minute of every hour, but only weekdays.

Answer

Every day at midnight.

Answer

Every hour.

Question 14

A system administrator wants to display all lines in /var/log/syslog that do NOT contain the string 'error'. Which command accomplishes this?

Accepted Answer

grep -v 'error' /var/log/syslog. The `grep -v` option inverts the match, displaying only lines that do NOT contain the pattern. Therefore, `grep -v 'error' /var/log/syslog` outputs all lines from the file that lack the string 'error', which directly fulfills the requirement.

Answer

grep -r 'error' /var/log/syslog

Answer

grep -l 'error' /var/log/syslog

Answer

grep -i 'error' /var/log/syslog

Question 15

A developer has a directory /home/user/project with many files and subdirectories. They need to change the group ownership of all .txt files to 'developers' and set permissions to 640. Which single command accomplishes this?

Accepted Answer

find /home/user/project -name '*.txt' -exec chown :developers {} \; -exec chmod 640 {} \;. It uses `find` to locate all `.txt` files under `/home/user/project`, then executes `chown :developers` to change the group ownership to 'developers' (the colon before the group name is the correct syntax for setting only the group), followed by `chmod 640` to set the permissions to read/write for the owner and read for the group. Using `-exec` twice in a single `find` command ensures both operations are applied to each matching file without needing a separate command.

Answer

find /home/user/project -name '*.txt' -exec chgrp developers {} \;

Answer

chmod -R 640 /home/user/project/*.txt

Answer

find /home/user/project -name '*.txt' -exec chmod 640 {} \;