Open source databases such as PostgreSQL are no longer treated only as developer tools. For many enterprises, the real question has shifted from brand comfort to engineering maturity.
For current Oracle databases, Data Pump is the preferred way to export a schema. The older exp/imp utilities are legacy tools and are mainly relevant to older environments. Export a schema with expdp expdp system@database \ schemas=SCOTT \ directory=DATA_PUMP_DIR \ dumpfile=scott_%U.dmp \ logfile=scott_export.log The Oracle directory object points to a server-side filesystem location. The database … Read more
Steps to recover or reinstall GRUB from live media or a rescue environment.
wget is useful when you need to download files from a web directory or mirror a simple documentation page for offline use. Example This command recursively downloads the linked page and the files needed to view it locally: Options used -r or –recursive: enable recursive download. –level=1: limit recursion depth to one level. -k or … Read more
The du command is the quick way to check how much disk space a directory is using on Linux or Unix systems. Check the size of a directory Example: Example output: Options used -s: show only the total size for the directory. -h: show the result in a human-readable format such as KB, MB or … Read more
How to schedule and cancel a Linux shutdown from the command line.
The find command is useful for locating files recursively and then taking action on them. When deleting files, it is safer to list the matches first and delete only after checking the output. List matching files first List all .tmp files below the current directory: List all .log files below the current directory: Delete after … Read more
In vi or vim, you can comment a range of lines by using a substitution command. This is handy when editing shell scripts, configuration files or temporary notes. Comment every line in the file Open the file in vi, press Esc, then run: This adds # at the start of every line. Use a different … Read more
To estimate the space used by a schema, sum the bytes allocated to that schema’s segments in DBA_SEGMENTS. SELECT owner, ROUND(SUM(bytes) / 1024 / 1024 / 1024, 2) AS size_gb FROM dba_segments WHERE owner = ‘SCOTT’ GROUP BY owner; Use the schema name in uppercase unless it was created with quoted mixed-case identifiers. If you … Read more
Explains half duplex and full duplex Ethernet links and how to check link settings in Linux.