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21 entries match these filters

• 0009 CSV to JSON converter A small command-line tool that turns a CSV file into a JSON array of objects, with optional number detection, custom delimiters and… Beginner · How-to · Any system Script CSV & JSON · Files & automation 15 Oct 2026
• 0067 Your first SQL queries: SELECT, WHERE, ORDER BY, LIMIT and GROUP BY Read data from a table, keep only the rows you want, sort them, take the first few, and summarize groups with COUNT,… Beginner · How-to · Any system Article Queries 15 Oct 2026
• 0074 pandas basics: read a CSV, filter rows and summarize with groupby Load a CSV into a pandas DataFrame, inspect it, filter rows with conditions, and compute totals per group, with the SQL equivalent… Intermediate · How-to · Any system Article Data analysis · Files & automation 15 Oct 2026
• 0075 CSV to JSON converter (Python, standard library) Convert any CSV file with a header row into a JSON array or JSON Lines. Handles quoted fields, a byte order mark,… Beginner · How-to · Any system Script CSV & JSON · Files & automation 15 Oct 2026
• 0198 Install PostgreSQL and connect with psql on Debian, Ubuntu and RHEL Install the PostgreSQL server from your distribution or the official PGDG repositories, start it, and open your first psql session as the… Beginner · How-to · Linux Article Install & connect 15 Oct 2026
• 0200 PostgreSQL roles, privileges and default privileges Create login and group roles, grant access to databases, schemas and tables, and use ALTER DEFAULT PRIVILEGES so tables created later get… Intermediate · How-to · Linux Article Roles & administration · Security & access 15 Oct 2026
• 0202 Back up and restore PostgreSQL with pg_dump, pg_restore and pg_dumpall Make logical backups of one database with pg_dump, of roles and the whole cluster with pg_dumpall, and restore them with pg_restore or… Beginner · How-to · Linux Article Backup & restore 15 Oct 2026
• 0205 Set up PostgreSQL streaming replication with a hot standby Step-by-step: prepare a primary, clone it with pg_basebackup, start a read-only standby that streams WAL, check it works, and understand promotion and… Advanced · How-to · Linux Article Replication & high availability 15 Oct 2026
• 0206 Nightly PostgreSQL backup script with pg_dump and rotation A bash script for cron that dumps cluster roles plus every database in custom format into a dated folder, checks each archive,… Intermediate · How-to · Linux Script Backup & restore 15 Oct 2026
• 0208 Check PostgreSQL replication lag with a monitoring script A bash check that detects whether it runs on a primary or a standby, measures replication lag in bytes and seconds, and… Advanced · How-to · Linux Script Replication & high availability 15 Oct 2026
• 0214 MySQL users and privileges: CREATE USER, GRANT and authentication plugins A MySQL account is a user name plus the host it connects from. You create it with CREATE USER, give it rights… Beginner · How-to · Linux Article Administration · Security & access 15 Oct 2026
• 0218 Setting up MySQL source-replica replication with GTIDs Step by step: configure a MySQL 8.4 source and replica with GTIDs, create the replication account, copy the data, connect the replica… Advanced · How-to · Linux Article Administration · Replication 15 Oct 2026
• 0219 mysqldump nightly backup with rotation (bash) A cron-ready bash script that dumps each MySQL or MariaDB database to its own compressed file with --single-transaction, verifies it and deletes… Intermediate · How-to · Linux Script Administration · Backup & restore 15 Oct 2026
• 0223 Oracle users, roles and tablespaces: setup script and usage report (SQL) A SQL*Plus/SQLcl script that creates a tablespace, a role and an application user inside a PDB, then reports tablespace usage from the… Intermediate · How-to · Any system Script Administration · Security & access 15 Oct 2026
• 0224 RMAN backup basics: ARCHIVELOG mode, a nightly backup script and restore Enable ARCHIVELOG mode, set an RMAN retention policy, run a nightly full backup with archived logs from cron, and learn the restore… Advanced · How-to · Linux Script Administration · Backup with RMAN 15 Oct 2026
• 0225 Oracle Data Pump: export and import schemas with expdp and impdp Data Pump moves schemas, tables or whole databases between Oracle databases as dump files. Set up a directory object, export with expdp… Intermediate · How-to · Linux, Windows Article Administration · Backup with RMAN 15 Oct 2026
• 0233 Turn on MongoDB authentication and create least-privilege users A fresh MongoDB install accepts connections without a password. Create a user administrator, enable authorization, then give each application and backup job… Intermediate · How-to · Linux Article Administration · Security & access 15 Oct 2026
• 0234 Nightly mongodump backup with rotation A bash script for cron that writes a compressed mongodump archive each night, keeps the password out of the process list, checks… Intermediate · How-to · Linux Script Administration · Database operations 15 Oct 2026
• 0237 Use Redis as a cache: TTLs, maxmemory and an eviction health report Set a memory limit and an eviction policy so Redis behaves like a cache, give keys TTLs, then run a bash report… Intermediate · How-to · Linux, macOS Script Administration & persistence · Basics 15 Oct 2026
• 0242 Database security checklist: access, encryption, exposure and patching A practical checklist for hardening any database server, with MongoDB and Redis examples: no public exposure, authentication, least privilege, TLS, protected backups,… Advanced · How-to · Linux Article Database operations · Security & access 15 Oct 2026
• 0243 Database backup strategy: the 3-2-1 rule and testing restores Keep three copies of your data on two kinds of storage with one copy offsite, choose dump or snapshot methods per database,… Intermediate · How-to · Linux Article Database operations · Security & access 15 Oct 2026