Shell Programming and Scripting

Hi,

In the script that i work now, I wrote the script such a way that the values retrieved using a tcl script is passed into a shell script to specify the path where the specific file needs to be sourced exists.

For eg: I got a path from the tcl script given below,

/A/B/C/D3/E/<File_name>

Here A, B, C, all are folders.

In the above example "D3" is the only variable keeps changing rest all are static.

My query is, some times the Variable retrieved from the tcl script "D3" might not exists so we are supposed to search for the lower version of "D3" that is "D2" and to fetch the file.

I dont know whether it can be achieved using for Loop, I need your guidance to resolve this issue.

D3 is the actual name? If not, what are the rules for this directory?
How many alpha bates? numbers? and upto which number you want check for the lower versions? like .. If not in D3, check D2, if again not, check D1?

you don't need a for loop, you need a while loop, you should test for the existence [ -e $directory_name ] of the D3 value in the while loop, and if not decrement the value, as we don't have the details of the contents of D3 (I'm assuming it's a hex value, for no good reason, and so easy to decrement)

anchal_khare:

D3 is the name i used for example;

3 alphabets and 4 numbers will be there altogether in the name of the directory .


eg: siv4018 ; this will be formed initially based on the input from the TCL script, in case if this directory doesn't exists it should search for siv4017 like wise it should be decremented one by one; in this eg upto "siv401" will be fixed and only the last numeric value alone should be considered.

Try this construct

Code:

while [ ! -e $filename ] && [ $(( ${#filename} - 1 )) -ne 0 ] 
   do  
      filename=${filename:0:$(( ${#filename} - 1 ))}$(( ${filename:$(( ${#filename} - 1 )) } -1))
   done
echo $filename

It decrements the final character until it equals zero, you'll have to check again for the existence of the file after the loop of course...

Better yet, you could do:

Code:

last_version=`ls -d siv[0-9]* | sort -n | tail -n 1`

That is,

Code:

dir0=siv4210
dirNoVer=${dir0%%[0-9]*}  #'siv'
dirLastVer=$(ls -d ${path}/${dirNoVer}[0-9]* | sort -n | tail -n 1)

mirni's suggestion is fine if there won't be a case where

Code:

ls siv*
siv4211 siv4215 siv4217
dir0=siv4216
...