August 2014 – Ryan Chapin's Website

Backspace, Delete, and/or Return Key Stops Working in Oracle SQL Developer

Posted on August 29, 2014March 28, 2021 by rchapin

So, I fire up SQL Developer to run some queries against a QC server and for some reason, I am no longer able to use the backspace, delete, or return keys to edit .sql files opened in the program.

I tried opening a new .sql file, and restarting SQL Developer. I then tried restarting Windows. None of those worked.

After a bit of searching I found a forum posting that indicated by going to Tools/Preferences/Accelerators and clicking the “Load Preset…” button in the bottom right of the dialog box would fix the problem. My guess is that some key mapping preference file had gotten corrupted some how and that by replacing it with a default that it fixes the problem.

After doing so, I was back in business.

Checking that Input or a Variable is an Integer in BASH

Posted on August 26, 2014March 28, 2021 by rchapin

Here is a quick snippet for checking whether or not a variable is a valid integer in BASH. It is also a howto for regular expressions in a shell script.

# Make sure that FOO is an integer
if [[ ! "$FOO" =~ ^[0-9]+$ ]]; then
        echo "The FOO was NOT an integer"
fi

How To Benchmark Disk I/O

Posted on August 14, 2014March 28, 2021 by rchapin

Here is a quick snipped on how to benchmark Disk I/O with dd.

time sh -c "dd if=/dev/zero of=/home/rchapin/test.zeros bs=1024k count=10000 && sync"

10000+0 records in
10000+0 records out
10485760000 bytes (10 GB) copied, 81.4124 s, 129 MB/s

real    1m21.950s
user    0m0.810s
sys     0m5.474s

Will do a write test of 10GB.

You can do a similar test and read from that file generated and write to another file or /dev/null to get an idea of the read speeds.

See the this link for more information.