tar command - how to archive files in Linux
The tar command in Linux is a go-to tool for creating backups, bundling files, and compressing archives.
Short for tape archive, tar lets you group files into archives commonly called tarballs and compress them using algorithms like gzip, bzip2, and xz.
If youโre packaging software or simply managing file storage, tar is a powerful tool to have in your Linux toolkit.
The tar command in Linux is a go-to tool for creating backups, bundling files, and compressing archives.
Short for tape archive, tar lets you group files into archives commonly called tarballs and compress them using algorithms like gzip, bzip2, and xz.
If youโre packaging software or simply managing file storage, tar is a powerful tool to have in your Linux toolkit.
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SQL Essential Concepts
๐ญ. ๐๐ป๐๐ฟ๐ผ ๐๐ผ ๐ฆ๐ค๐: Definition, purpose, relational DBs, DBMS.
๐ฎ. ๐๐ฎ๐๐ถ๐ฐ ๐ฆ๐ค๐ ๐ฆ๐๐ป๐๐ฎ๐ : SELECT, FROM, WHERE, ORDER BY, GROUP BY.
๐ฏ. ๐๐ฎ๐๐ฎ ๐ง๐๐ฝ๐ฒ๐: Integer, floating-point, character, date, VARCHAR, TEXT, BLOB, BOOLEAN.
๐ฐ. ๐ฆ๐๐ฏ ๐น๐ฎ๐ป๐ด๐๐ฎ๐ด๐ฒ๐: DML, DDL, DQL, DCL, TCL.
๐ฑ. ๐๐ฎ๐๐ฎ ๐ ๐ฎ๐ป๐ถ๐ฝ๐๐น๐ฎ๐๐ถ๐ผ๐ป: INSERT, UPDATE, DELETE.
๐ฒ. ๐๐ฎ๐๐ฎ ๐๐ฒ๐ณ๐ถ๐ป๐ถ๐๐ถ๐ผ๐ป: CREATE, ALTER, DROP, Indexes.
๐ณ. ๐ค๐๐ฒ๐ฟ๐ ๐๐ถ๐น๐๐ฒ๐ฟ๐ถ๐ป๐ด ๐ฎ๐ป๐ฑ ๐ฆ๐ผ๐ฟ๐๐ถ๐ป๐ด: WHERE, AND, OR conditions, ascending, descending.
๐ด. ๐๐ฎ๐๐ฎ ๐๐ด๐ด๐ฟ๐ฒ๐ด๐ฎ๐๐ถ๐ผ๐ป: SUM, AVG, COUNT, MIN, MAX.
๐ต. ๐๐ผ๐ถ๐ป๐ ๐ฎ๐ป๐ฑ ๐ฅ๐ฒ๐น๐ฎ๐๐ถ๐ผ๐ป๐๐ต๐ถ๐ฝ๐: INNER JOIN, LEFT JOIN, RIGHT JOIN, Self-Joins, Cross Joins, FULL OUTER JOIN.
๐ญ๐ฌ. ๐ฆ๐๐ฏ๐พ๐๐ฒ๐ฟ๐ถ๐ฒ๐: Filtering data, aggregating data, joining tables, correlated subqueries.
๐ญ๐ญ. ๐ฉ๐ถ๐ฒ๐๐: Creating, modifying, dropping views.
๐ญ๐ฎ. ๐ง๐ฟ๐ฎ๐ป๐๐ฎ๐ฐ๐๐ถ๐ผ๐ป๐: ACID properties, COMMIT, ROLLBACK, SAVEPOINT, ROLLBACK TO SAVEPOINT.
๐ญ๐ฏ. ๐ฆ๐๐ผ๐ฟ๐ฒ๐ฑ ๐ฃ๐ฟ๐ผ๐ฐ๐ฒ๐ฑ๐๐ฟ๐ฒ๐: CREATE, ALTER, DROP, EXECUTE, User-Defined Functions (UDFs).
๐ญ๐ฐ. ๐ง๐ฟ๐ถ๐ด๐ด๐ฒ๐ฟ๐: Trigger events, trigger execution, and syntax.
๐ญ๐ฑ. ๐ฆ๐ฒ๐ฐ๐๐ฟ๐ถ๐๐ ๐ฎ๐ป๐ฑ ๐ฃ๐ฒ๐ฟ๐บ๐ถ๐๐๐ถ๐ผ๐ป๐: CREATE USER, GRANT, REVOKE, ALTER USER, DROP USER.
๐ญ๐ฒ. ๐ข๐ฝ๐๐ถ๐บ๐ถ๐๐ฎ๐๐ถ๐ผ๐ป๐: Indexing strategies, query optimization.
๐ญ๐ณ. ๐ก๐ผ๐ฟ๐บ๐ฎ๐น๐ถ๐๐ฎ๐๐ถ๐ผ๐ป: 1NF, 2NF, 3NF, BCNF.
๐ญ๐ด. ๐ก๐ผ๐ฆ๐ค๐ ๐๐ฎ๐๐ฎ๐ฏ๐ฎ๐๐ฒ๐: MongoDB, Cassandra, and key differences.
๐ญ๐ต. ๐๐ฎ๐๐ฎ ๐๐ป๐๐ฒ๐ด๐ฟ๐ถ๐๐: Primary key, foreign key.
๐ฎ๐ฌ. ๐๐ฑ๐๐ฎ๐ป๐ฐ๐ฒ๐ฑ ๐ฆ๐ค๐ ๐ค๐๐ฒ๐ฟ๐ถ๐ฒ๐: Window functions, Common Table Expressions (CTES).
๐ญ. ๐๐ป๐๐ฟ๐ผ ๐๐ผ ๐ฆ๐ค๐: Definition, purpose, relational DBs, DBMS.
๐ฎ. ๐๐ฎ๐๐ถ๐ฐ ๐ฆ๐ค๐ ๐ฆ๐๐ป๐๐ฎ๐ : SELECT, FROM, WHERE, ORDER BY, GROUP BY.
๐ฏ. ๐๐ฎ๐๐ฎ ๐ง๐๐ฝ๐ฒ๐: Integer, floating-point, character, date, VARCHAR, TEXT, BLOB, BOOLEAN.
๐ฐ. ๐ฆ๐๐ฏ ๐น๐ฎ๐ป๐ด๐๐ฎ๐ด๐ฒ๐: DML, DDL, DQL, DCL, TCL.
๐ฑ. ๐๐ฎ๐๐ฎ ๐ ๐ฎ๐ป๐ถ๐ฝ๐๐น๐ฎ๐๐ถ๐ผ๐ป: INSERT, UPDATE, DELETE.
๐ฒ. ๐๐ฎ๐๐ฎ ๐๐ฒ๐ณ๐ถ๐ป๐ถ๐๐ถ๐ผ๐ป: CREATE, ALTER, DROP, Indexes.
๐ณ. ๐ค๐๐ฒ๐ฟ๐ ๐๐ถ๐น๐๐ฒ๐ฟ๐ถ๐ป๐ด ๐ฎ๐ป๐ฑ ๐ฆ๐ผ๐ฟ๐๐ถ๐ป๐ด: WHERE, AND, OR conditions, ascending, descending.
๐ด. ๐๐ฎ๐๐ฎ ๐๐ด๐ด๐ฟ๐ฒ๐ด๐ฎ๐๐ถ๐ผ๐ป: SUM, AVG, COUNT, MIN, MAX.
๐ต. ๐๐ผ๐ถ๐ป๐ ๐ฎ๐ป๐ฑ ๐ฅ๐ฒ๐น๐ฎ๐๐ถ๐ผ๐ป๐๐ต๐ถ๐ฝ๐: INNER JOIN, LEFT JOIN, RIGHT JOIN, Self-Joins, Cross Joins, FULL OUTER JOIN.
๐ญ๐ฌ. ๐ฆ๐๐ฏ๐พ๐๐ฒ๐ฟ๐ถ๐ฒ๐: Filtering data, aggregating data, joining tables, correlated subqueries.
๐ญ๐ญ. ๐ฉ๐ถ๐ฒ๐๐: Creating, modifying, dropping views.
๐ญ๐ฎ. ๐ง๐ฟ๐ฎ๐ป๐๐ฎ๐ฐ๐๐ถ๐ผ๐ป๐: ACID properties, COMMIT, ROLLBACK, SAVEPOINT, ROLLBACK TO SAVEPOINT.
๐ญ๐ฏ. ๐ฆ๐๐ผ๐ฟ๐ฒ๐ฑ ๐ฃ๐ฟ๐ผ๐ฐ๐ฒ๐ฑ๐๐ฟ๐ฒ๐: CREATE, ALTER, DROP, EXECUTE, User-Defined Functions (UDFs).
๐ญ๐ฐ. ๐ง๐ฟ๐ถ๐ด๐ด๐ฒ๐ฟ๐: Trigger events, trigger execution, and syntax.
๐ญ๐ฑ. ๐ฆ๐ฒ๐ฐ๐๐ฟ๐ถ๐๐ ๐ฎ๐ป๐ฑ ๐ฃ๐ฒ๐ฟ๐บ๐ถ๐๐๐ถ๐ผ๐ป๐: CREATE USER, GRANT, REVOKE, ALTER USER, DROP USER.
๐ญ๐ฒ. ๐ข๐ฝ๐๐ถ๐บ๐ถ๐๐ฎ๐๐ถ๐ผ๐ป๐: Indexing strategies, query optimization.
๐ญ๐ณ. ๐ก๐ผ๐ฟ๐บ๐ฎ๐น๐ถ๐๐ฎ๐๐ถ๐ผ๐ป: 1NF, 2NF, 3NF, BCNF.
๐ญ๐ด. ๐ก๐ผ๐ฆ๐ค๐ ๐๐ฎ๐๐ฎ๐ฏ๐ฎ๐๐ฒ๐: MongoDB, Cassandra, and key differences.
๐ญ๐ต. ๐๐ฎ๐๐ฎ ๐๐ป๐๐ฒ๐ด๐ฟ๐ถ๐๐: Primary key, foreign key.
๐ฎ๐ฌ. ๐๐ฑ๐๐ฎ๐ป๐ฐ๐ฒ๐ฑ ๐ฆ๐ค๐ ๐ค๐๐ฒ๐ฟ๐ถ๐ฒ๐: Window functions, Common Table Expressions (CTES).
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SQL, or Structured Query Language, is a domain-specific language used to manage and manipulate relational databases.
A - Aggregate Functions: Functions like COUNT, SUM, AVG, MIN, and MAX used to perform operations on data in a database.
B - BETWEEN: A SQL operator used to filter results within a specific range.
C - CREATE TABLE: SQL statement for creating a new table in a database.
D - DELETE: SQL statement used to delete records from a table.
E - EXISTS: SQL operator used in a subquery to test if a specified condition exists.
F - FOREIGN KEY: A field in a database table that is a primary key in another table, establishing a link between the two tables.
G - GROUP BY: SQL clause used to group rows that have the same values in specified columns.
H - HAVING: SQL clause used in combination with GROUP BY to filter the results.
I - INNER JOIN: SQL clause used to combine rows from two or more tables based on a related column between them.
J - JOIN: Combines rows from two or more tables based on a related column.
K - KEY: A field or set of fields in a database table that uniquely identifies each record.
L - LIKE: SQL operator used in a WHERE clause to search for a specified pattern in a column.
M - MODIFY: SQL command used to modify an existing database table.
N - NULL: Represents missing or undefined data in a database.
O - ORDER BY: SQL clause used to sort the result set in ascending or descending order.
P - PRIMARY KEY: A field in a table that uniquely identifies each record in that table.
Q - QUERY: A request for data from a database using SQL.
R - ROLLBACK: SQL command used to undo transactions that have not been saved to the database.
S - SELECT: SQL statement used to query the database and retrieve data.
T - TRUNCATE: SQL command used to delete all records from a table without logging individual row deletions.
U - UPDATE: SQL statement used to modify the existing records in a table.
V - VIEW: A virtual table based on the result of a SELECT query.
W - WHERE: SQL clause used to filter the results of a query based on a specified condition.
X - (E)XISTS: Used in conjunction with SELECT to test the existence of rows returned by a subquery.
Z - ZERO: Represents the absence of a value in numeric fields or the initial state of boolean fields.
A - Aggregate Functions: Functions like COUNT, SUM, AVG, MIN, and MAX used to perform operations on data in a database.
B - BETWEEN: A SQL operator used to filter results within a specific range.
C - CREATE TABLE: SQL statement for creating a new table in a database.
D - DELETE: SQL statement used to delete records from a table.
E - EXISTS: SQL operator used in a subquery to test if a specified condition exists.
F - FOREIGN KEY: A field in a database table that is a primary key in another table, establishing a link between the two tables.
G - GROUP BY: SQL clause used to group rows that have the same values in specified columns.
H - HAVING: SQL clause used in combination with GROUP BY to filter the results.
I - INNER JOIN: SQL clause used to combine rows from two or more tables based on a related column between them.
J - JOIN: Combines rows from two or more tables based on a related column.
K - KEY: A field or set of fields in a database table that uniquely identifies each record.
L - LIKE: SQL operator used in a WHERE clause to search for a specified pattern in a column.
M - MODIFY: SQL command used to modify an existing database table.
N - NULL: Represents missing or undefined data in a database.
O - ORDER BY: SQL clause used to sort the result set in ascending or descending order.
P - PRIMARY KEY: A field in a table that uniquely identifies each record in that table.
Q - QUERY: A request for data from a database using SQL.
R - ROLLBACK: SQL command used to undo transactions that have not been saved to the database.
S - SELECT: SQL statement used to query the database and retrieve data.
T - TRUNCATE: SQL command used to delete all records from a table without logging individual row deletions.
U - UPDATE: SQL statement used to modify the existing records in a table.
V - VIEW: A virtual table based on the result of a SELECT query.
W - WHERE: SQL clause used to filter the results of a query based on a specified condition.
X - (E)XISTS: Used in conjunction with SELECT to test the existence of rows returned by a subquery.
Z - ZERO: Represents the absence of a value in numeric fields or the initial state of boolean fields.
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