Author Archives: Ahmed Tawfik

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About Ahmed Tawfik

Cybersecurity Professional, Systems Engineer, OSS & Linux Geek

How to get number of cores on your Linux Box

cat /proc/cpuinfo | grep “model name” | wc -l example output: 24 This means that you have 24 cores on your server.

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How to determine history of DB startup in Oracle 11g

SQL> SELECT STARTUP_TIME FROM dba_hist_database_instance ORDER BY startup_time DESC; STARTUP_TIME ————————————————————————— 29-SEP-13 03.43.07.000 AM 29-SEP-13 03.42.31.000 AM 29-SEP-13 03.12.45.000 AM 29-SEP-13 03.11.28.000 AM 28-SEP-13 11.56.35.000 PM 07-SEP-13 10.04.07.000 PM 6 rows selected. Credit goes to Abdulrahman Galal from Oracle.

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Replacing a string with another in a text file using sed

sed -i ‘s/old-test/new-text/g’ filename This replaces the word old-test with the word new-text in the file named filename.

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Delete files older than X days

find /path/to/folder -mtime +14 -exec rm {} \; This finds all files within that folder that are older than 14 days, then executes rm on them

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