MySQL data files .MYD, .MYI, and .frm

 Linux, mysql, UNIX  26 Responses »
Mar 202009

A MySQL database creates a number of different data files in the mysql data directory (typically /var/lib/mysql). The following are the differences between the data files created:

File Extension Purpose
.frm table definition
.MYD table data
.MYI table indices

I believe these files are created for both MyISAM and InnoDB table types because the MySQL documentation references these types with respect to MyISAM and I definitely see them on my InnoDB tables.

I couldn’t find this information directly in the MySQL documentation and google wasn’t much help either so hopefully this post will save someone else some search effort.

Posted by kevin at 9:49 am  Tagged with: ,

Doing UNIX Shell For Loops The Right Way

 Linux, UNIX  No Responses »
Mar 162009

Typically for loops in UNIX shell look like this:

for file in `ls *.c`
do
    cmd $file
done

However, the above has a serious problem in that it does not handle spaces in file names and will actually split the filename in two.

The following is a solution in bash:

files=(*.c)
for f in “${files[@]}”
do
    cmd "$f"
done

But my favourite way to perform a loop and probably the most elegant solution is to use file globbing:

for f in *.c
do
    cmd "$f"
done
Posted by kevin at 3:49 pm  Tagged with: ,

UNIX Access, Modify, and Change Times

 Linux, UNIX  7 Responses »
Mar 312008

What is the difference between UNIX Access, Modify, and Change Times?

This is a silly little thing that I consistently forget … or at least forget some of the subtle differences between these three measures.
Continue reading »

Posted by kevin at 8:22 pm  

Using The Korn Shell and Not Going Mad

 Linux, UNIX  No Responses »
Feb 182008

This article describes common functionality that is often thought lacking in ksh but is just hiding in unintuitive corners (such as command line completion!)
Continue reading »

Posted by kevin at 11:50 am  Tagged with: ,
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