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GK One-Line Question & Answer

15541+ short questions with short answers, covering every category and sub-category on the site — no long articles to scroll through. Good for a fast recap before an exam, or a few minutes of daily practice.

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Computer Fundamentals → Introduction to Computer 39

Which Linux command changes directory?
cd
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chmod in Linux is used to?
Change file permissions
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grep command in Linux?
Search text patterns in files
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sudo in Linux means?
Super user do
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Which Linux command shows disk usage?
df -h (disk free) and du -sh
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ping command tests?
Network connectivity and latency
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Which command installs packages in Ubuntu?
apt install
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Process 1 (PID 1) in Linux is?
init/systemd
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Which Linux command shows running processes?
ps
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SIGKILL signal in Linux?
Forcefully terminates process — cannot be caught or ignored
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Linux root user has UID?
0
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Encrypted passwords in Linux are stored in?
/etc/shadow
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Which is the correct SQL to select all columns?
SELECT *
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SQL LIKE wildcard for multiple characters is?
%
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PRIMARY KEY constraint?
Uniquely identifies each record, cannot be null
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FOREIGN KEY creates relationship between?
Two different tables
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Which SQL command modifies existing records?
UPDATE
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Index in database improves?
Data retrieval speed
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Normalization in databases aims to?
Reduce data redundancy and improve integrity
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Which JOIN returns only matching rows?
INNER JOIN
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LEFT JOIN returns?
All rows from left table plus matching from right (NULL where no match)
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SQL stored procedure advantages include?
Pre-compiled execution, reduced network traffic, code reuse
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SQL VIEW is?
Virtual table based on a query
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ACID property Atomicity means?
All operations in a transaction succeed or none do
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Which is NOT a valid SQL aggregate function?
FIRST()
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1's complement of binary 1010 is?
0101
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Binary 10000 equals decimal?
16
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Decimal 128 in binary is?
10000000
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Parity check detects how many bit errors?
Single bit errors only
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ASCII code of uppercase A is?
65
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ASCII code of lowercase a is?
97
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ASCII code 32 represents?
Space character
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UTF-8 uses how many bytes for ASCII characters?
1
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IEEE 754 single precision uses how many bits?
32
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Boolean AND of 1 AND 0?
0
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Boolean NOR of 0 NOR 0?
1
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Sum of Products (SOP) form is?
OR of AND terms
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Karnaugh Map is used for?
Simplifying Boolean expressions by grouping adjacent minterms
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Half adder outputs are?
Sum (A XOR B) and Carry (A AND B)
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Computer Fundamentals → Number System 1

Hexadecimal FF in decimal is?
255
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