Adnan Khurshid on April 5th, 2011

A crontab contains entries for a cron job. Entries in the crontab are separated by newline characters. Each crontab contains six fields separated by spaces as shown below: Minute Hour Day Month Weekday Command Each field is explained below: Minute: 0 ~ 59 Hour: 0 ~ 23 Day: 1 ~ 31 Month: 1 ~ 12 […]

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Adnan Khurshid on April 4th, 2011

For large output which is not able to fit in a single window, scrolling the results can skip data while it looks messy as well. to get rid of scrolling, you can use the command “set pause on”. With pause ON, the output will come in small chunks and will continue only when you press […]

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Adnan Khurshid on April 4th, 2011

This post will guide you how you can play with SQL using the interactive variable values inside the statement. To begin with, suppose we even don’t know which table we want to query from. To check all the tables inside the logged in database, you can query the TABLE_NAME from user_tables. To get all the […]

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Adnan Khurshid on April 4th, 2011

While typing commands on a unix system, removing a miss-typed character by the backspace writes down a character ^H instead. To remove a character, you must use Ctrl+BackSpace instead. However, this exercise is quite frustrating for the users. To get rid of this, use stty erase command as demonstrated below: root@mms1 # ls -l^H^H^H^H ls: […]

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This is one of the most commonly observed error in Oracle database. The exact error description is as follows: ERROR: ORA-01034: ORACLE not available ORA-27101: shared memory realm does not exist SUN OS Error: 2: No such file or directory Due to this error, the DBA is unable to login to the SQL prompt. This […]

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