Shell Programming and Scripting

I have just recently decided to install Unix on one of my home computers, and I am enjoying it so far. However, I have no knowledge of writing computer programs or scripts.
What I need to accomplish is a way for me to create backup copies of certain files, but I want to be able to just type all of the files that I need backed up all at once, instead of copying them separately.
For example:

$ mybackups file1 file2 file3....file10

and I would like to keep the original file names, but have each one end in .bk or something to let me know it is a backup.

I probably would also need a message displayed if the command is entered without any files listed, or if there is an error reading a file, but then continue processing the rest of the files.

I bought the Unix for Dummies book, and I understand alot of the stuff, but when it comes to writing scripts...well, it's a little tough trying to learn from a book.

Could somebody please help me out with this? I am trying so hard not to succumb to the temptation of reinstalling windows! LOL

Thanks

Here's a script that I use. It's similar to the one you describe. Customise it how you want.

Code:

#----script to backup files

if [ $# -lt 1 ]
then
   echo Usage: mkbak filename
   exit
fi

JJJ=`date '+%j'`

while [ $# -gt 0 ]
do
   echo $1
   FILE=$1
   #----check file exists
   if [ ! -f $FILE ]
   then
      echo Error: File \'$FILE\' not found!!
   else
      if [ -d .bkup ]
      then
          DESTFILE=.bkup/$FILE.$JJJ
      else
          DESTFILE=$FILE.$JJJ
      fi
      cp $FILE $DESTFILE
      gzip -9nf $DESTFILE
      ls -l $DESTFILE.gz
   fi
   shift
done

Thanks for the reply. I can see where you're going with that, but what I had in mind was something like this which I wrote in my version of pseudocode:

For each file listed as an argument
Create a backup copy with a .bk extension
If no files are listed as arguments
then display an error message
If file isn't readable
then display an error message
Process next file

Sorry looking pseudocode, huh? Hey, it's my first time...give me a break. LOL

Thanks

Ygor,

I like your pic by the way. Pretty cool!

he posted his working version of what you asked for. to change it for your needs you need to take some ownership and incorporate his work into your own.

we are here to help, in doing so you have to learn and alter what we give you to suit your needs. we are a support forum not a script factory.

Hey, sorry man! I didn't mean any harm. It's just that I already specified that I had no knowledge of programming.
I have no idea of what to do with that script to modify it, that's all.
For example, I am a linguistics major. Now you want to learn how to have a basic conversation in a chosen language, say Italian, and you ask me how to tell a woman you think she is beautiful.
Now, I tell you, well, the verb "to think" is "pensare", "beautiful" is "bella", and then there's "io" for "I", and you is "tu". Also you will need to incorporate the verb "to be", which is "essere"...now go ahead and form the sentence based only on that information.
Do you think you could, providing you weren't familiar with the Italian language? All you wanted to know was how to say a particular sentence, not force yourself to learn the entire language in order to do so, right?
I guess I came to the wrong place for help then.

Well, thanks again Ygor for trying to help me..I appreciate the effort.

i completely know that it is a bit different and hard to get started. check out our faq for various books to check out about scripting.

if you know shell you are useing most book stores have a book on "Learning that specific shell" and once you read it you will have a MUCH better grasp at shell scripting.