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# 1  
Old 08-20-2019
Replace a string based on input
I am trying to read a value from a mapping file and would need to replace the value based on country parameter
Code:
source_table_@ctry_final
Expected
final_var=source_table_aus_final

Code:
If the country is in nz,usa,uk then 
final_var=diff_table_nz_final
final_var=diff_table_usa_final
like that

else
final_var=source_table_aus_final

Code:







My try




Code:



final_var=$(echo "source_table_@ctry_final"| sed -e "s/\@ctry/${ctry_input}/")















        

        

       



            
            
            
            


            

            
            




            
                
            

            

        



        


        


 


        

        
        

        


 

            
        






     

          
     





      

          
      











		

















    
    

        

            



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Please state the operating system, including version, and the shell you are using.



This works in ksh93 (Version AJM 93u+ 2012-08-01) on Ubuntu 18.04.3 LTS:




Code:



$ src=source_table_@ctry_final
$ rplst=nz,usa,uk
$ echo ${src/@ctry/{$rplst}}
source_table_nz_final source_table_usa_final source_table_uk_final







Strangely enough, it doesn't work with bash (4.4.20(1)-release):


Code:



$ echo ${src/ctry/{$rplst}}
source_table_{nz,usa,uk_final}







If anybody knows why, could we start a new thread on this, uh, feature?

[..]







        
          
            

                

                
                    
                        Last edited by Scrutinizer; 08-20-2019 at 06:23 AM..
                    
                    
                
            

   
        

        

       



            
            
            
            


            

            
            




            
                
            

            

        



        


        


 


        

        
        

        


 

            
        




    

        

          
        

    

    

       

          
        

    









		

















    
    

        

            



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Quote:



    
      

        Originally Posted by apmcd47
        
        
        
      

    
...

Strangely enough, it doesn't work with bash (4.4.20(1)-release):


Code:



$ echo ${src/ctry/{$rplst}}
 source_table_{nz,usa,uk_final}







...

    






In bash, the unloved, deprecated eval helps:








Code:



eval echo ${src/@ctry/{$rplst\}}
 source_table_nz_final source_table_usa_final source_table_uk_final







and, no, the $ and { need to be in that sequence in order to make it a "brace expansion", which, in turn, can only be recognized / evaluated by the evil eval.







        

        

       



            
            
            
            


            

            
            




            
                
            

            

        



        


        


 


        

         



	

           

                  

	
                
				
					
This User Gave Thanks to RudiC For This Post:

				
            

			
			

        

		
 apmcd47

    





        

        


 

            
        









		

















    
    

        

            



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But expected would be below.  source string needs to be replaced with diff






Code:



diff_table_usa_final







Shell is bash







        

        

       



            
            
            
            


            

            
            




            
                
            

            

        



        


        


 


        

        
        

        


 

            
        









		

















    
    

        

            



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Quote:



    
      

        Originally Posted by Master_Mind
        
        
        
      

    
I am trying to read a value from a mapping file and would need to replace the value based on country parameter

    




 How is that "country parameter" supplied and evaluated?





Quote:



    
    
 


Code:



source_table_@ctry_final
Expected
final_var=source_table_aus_final






    




The @ctry part has which value, for _aus_ to be part of the final string?







Quote:



    
    


Code:



If the country is in nz,usa,uk then 
 final_var=diff_table_nz_final
final_var=diff_table_usa_final
like that

else
 final_var=source_table_aus_final






    




Which table is relevant - diff_table or source_table - or is the distinction part of the problem?











Quote:



    
    


Code:










My try




Code:



final_var=$(echo "source_table_@ctry_final"| sed -e "s/\@ctry/${ctry_input}/")






    




What is and which value has ctry_input? Where does it come into play?







        

        

       



            
            
            
            


            

            
            




            
                
            

            

        



        


        


 


        

        
        

        


 

            
        









		

















    
    

        

            



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It is because of the parsing order of the shell. In bash brace expansions are performed before any of the other expansions, hence the  need for eval (usual caution applies (security)!) for a second round of expansions after the first round.







        
          
            

                

                
                    
                        Last edited by Scrutinizer; 08-20-2019 at 06:35 AM..
                    
                    
                
            

   
        

        

       



            
            
            
            


            

            
            




            
                
            

            

        



        


        


 


        

        
        

        


 

            
        









		

















    
    

        

            



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Unlike bash, ksh93 seems to do variable expansion before brace expansion. (Scrutinizer just said it.)



Master_Mind, I am not fully getting your requirement, but here is how you can adjust the ctry_input variable




Code:



#!/bin/sh
ctry_input=$1
case $ctry_input in
nz|usa|uk)
;;
*)
  ctry_input=aus
;;
esac
sed "s/@ctry/$ctry_input/"







This sample script you can run with a "uk" or "usa" argument, for example




Code:



sh sample.sh uk < inputfile







--- Post updated at 12:39 ---



To meet your sourc/diff replacement requirement, you can move the sed into the case-branch:




Code:



#!/bin/sh
ctry_input=$1
case $ctry_input in
nz|usa|uk)
  sed "s/@ctry/$ctry_input/
  s/source_table/diff_table/"
;;
*)
  ctry_input=aus
  sed "s/@ctry/$ctry_input/"
;;
esac















        

        

       



            
            
            
            


            

            
            




            
                
            

            

        



        


        


 


        

        
        

        


 

            
        




    

         

          
        

    

    

       

          
        

    









		








            

        


        
        



        



        
        

            


                
                    
                        

                        
                    
                    
                

                    


                                    

                                        
                                    

                                

                        

                    		
                
            




        





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