Unable to increment last 2 digit of variable declared in file using script - shell

Question

I have the file given below:
elix554bx.xayybol.42> vi setup.REVISION
# Revision information
setenv RSTATE R24C01
setenv CREVISION X3
exit
My requirement is to read RSTATE from file and then increment last 2 digits of RSTATE in setup.REVISION file and overwrite into same file.
Can you please suggest how to do this?

Answer 1

If you're using vim, then you can use the sequence:
/RSTATE/
$<C-a>:x
The first line is followed by a return and searches for RSTATE. The second line jumps to the end of the line and uses Control-a (shown as <C-a> above, and in the vim documentation) to increment the number. Repeat as often as you want to increment the number. The :x is also followed by a return and saves the file.
The only tricky bit is that the leading 0 on the number makes vim think the number is in octal, not decimal. You can override that by using :set nrformats= followed by return to turn off octal and hex; the default value is nrformats=octal,hex.
You can learn an awful lot about vim from the book Practical Vim: Edit Text at the Speed of Thought by Drew Neil. This information comes from Tip 10 in chapter 2.

Answer 2

Here's an awk one-liner type solution:
awk '{
if ( $0 ~ 'RSTATE' ) {
match($0, "[0-9]+$" );
sub( "[0-9]+$",
sprintf( "%0"RLENGTH"d", substr($0, RSTART, RSTART+RLENGTH)+1 ),
$0 );
print; next;
} else { print };
}' setup.REVISION > tmp$$
mv tmp$$ setup.REVISION
Returns:
setenv RSTATE R24C02
setenv CREVISION X3
exit
This will handle transitions from two to three to more digits appropriately.

Answer 3

I wrote for you a class.
class Reader
{
public string ReadRs(string fileWithPath)
{
string keyword = "RSTATE";
string rs = "";
if(File.Exists(fileWithPath))
{
StreamReader reader = File.OpenText(fileWithPath);
try
{
string line = "";
bool finded = false;
while (reader != null && !finded)
{
line = reader.ReadLine();
if (line.Contains(keyword))
{
finded = true;
}
}
int index = line.IndexOf(keyword);
rs = line.Substring(index + keyword.Length +1, line.Length - 1 - (index + keyword.Length));
}
catch (IOException)
{
//Error
}
finally
{
reader.Close();
}
}
return rs;
}
public int GetLastTwoDigits(string rsState)
{
int digits = -1;
try
{
int length = rsState.Length;
//Get the last two digits of the rsstate
digits = Int32.Parse(rsState.Substring(length - 2, 2));
}
catch (FormatException)
{
//Format Error
digits = -1;
}
return digits;
}
}
You can use this as exists
Reader reader = new Reader();
string rsstate = reader.ReadRs("C://test.txt");
int digits = reader.GetLastTwoDigits(rsstate);