Shell Programming and Scripting

His may seem simple to many but I have no clue
Need some urgent help please

How can I make this statement evaluate to true if the actual DataFile can have an extension of either .dat or .txt

what I'm trying to say is my datafile could have a name like
ABC_20070323_xyz.dat
or
ABC_20070323_xyz.txt

now the trick is also in the if statement
These for example are now valid
ABC_20070323_xyz.dat.gz
or
ABC_20070323_xyz.dat.Z
or
ABC_20070323_xyz.txt

notice the .txt file can also have the option of no compression


ControlFileName=${ControlFile##*/};
DataFile="${SOURCE_DATA_PATH}/${ControlFileName%.*}.dat";

if [[ -f "${DataFile}" ]]; then
X=1; # Do nothing
elif [[ -f "${DataFile}.gz" ]]; then
DataFile=${DataFile}.gz;
elif [[ -f "${DataFile}.Z" ]]; then
DataFile=${DataFile}.Z;
else
Log ERROR "Could not find data file for Data File=${DataFile} [or .dat.gz or .dat.Z]";
returnStatus=1;
break;
fi;

In ksh you can make patterns that will match any of those possible names, but an if statement using them would fail if more than one name matches the pattern. So you could loop through all of the names...

$ ls
xyz.txt.Z xyz.txt.gz
$ name=xyz
$ for f in ${name}.@(dat|txt)?(.gz|.Z) ; do echo $f ; done
xyz.txt.Z
xyz.txt.gz
$

Or if you don't care which file you have, maybe something like this:

$ list=$(echo ${name}.@(dat|txt)?(.gz|.Z))
$ echo $list
xyz.txt.Z xyz.txt.gz
$ onename=${list%% *}
$ echo $onename
xyz.txt.Z
$