using sed for changing file names

[jms318]

Ok here is a problem that stumps me scripting with sed

I get we can have sed search ad replace for example i have a file called test_add1.cpp
and so on with several add with a number followed by the .cpp
if i wanted to change test_ to finish i would

 sed s/test_\(.*\)/final\1/'

and this would change all instances.

How about if i need to write a script that could change delete a portion of the file name by passing two arguments from the command line
like if the script was called dropend

$./dropend myfile.bak .bak

and the result would be the file called myfile and you can always ussume there will always be a period.

im thinking something like using a

newfilename=$ (echo $1| sed with the back quote technique)

and then
doing something like

mv $1 $newfilename

but i have no idea where to use $2 which is the second argument passed in to the script from the command line. I am stumped here.

Please if some one can tell me where im going wrong?

Thanks,
Joe

[birdman]

I'll give you a start and let you work from it:

echo myfile.bak | sed "s/\.bak//"

Cheers

[ghostdog74]

no need external commands in bash

a="hello.bak"
echo ${a%.bak}

[jms318]

hey bird man thank you. I am using a script that works where you give it a file name and then the second argment giving is what you waant deleted off the file. It will not always start at the period example
[CODE] $dropend example.exe.tar .tar [CODE]

the script needs to pass the two arguments and make the change to the file name. so i cant hard code the files name or the part needing deleted. i need something that used $1 and $2 only im not getting how i can pass this to sed ???

[jms318]

hey thanks birdman you got me thinking on the right path

her is the new script

#script that drops desired parts off #filenames
newfile=`echo $1 | sed "s/$2//"
mv $1 $newfile

works like a charm thank you so much