How to use the Command-line Parameters to select then change a group of filenames

Question

I have been using a simple shell script placed in my user/.bin folder; Its job is very simple, copy specified files $1 and rename to $2; at least I had thought it to be that simple ...

The situation of use is this, I have a file nomenclature for my programming notes. The system is simple, an augmenting number followed by a letter, the rest of the file name contains only letters and underscores. Notes for a certain topic are called: 16115P-foobar.md whilst the code files for that topic are: 16115P-foobar.c 16115P-barfoo.h etc.

As the program progresses with each lesson, I am copying all program files before modifying them; So as to have files of each step of the course. As it is required of me to modify the program using the lessons topic; the first thing I do is copy and rename the files. The script is supposed to duplicate each file and rename them, changing only the sequential number, which is of my standard nomenclature:

e.g. 16115P-foobar.c is to be changed to 17121P-foobar.c ... etc.

The new number is specified by the user (my self only) by way of the second command line parameter; not automated by the script.

#!/bin/bash

for filename in $1*
do
    #
    # Copy and rename files
    #
    newname=`echo "$filename" | tr "$1" "$2"`
    echo $filename $newname
    cp $filename $newname
done

When I parse my file names like so:

:~/blah/blah/code$ copy_and_rename 16115P 17121P
16115P-file.c 27221P-file.c
16115P-input.c 27221P-input.c
16115P-main.c 27221P-main.c
16115P-output.c 27221P-output.c
16115P-recordshop.h 27221P-recordshop.h
16115P-utils.c 27221P-utils.c

I see now that tr is not the correct command to use here; I would appreciate some help.

Kind regards.

Answer 1

This is a task more suitable for regular expressions. Here I use regular expressions with awk ( since I am not familiar with rename command and perl regex, yes - shame on me ). Basic idea is that we take filename, get rid of all the numbers ( assuming you are pretty good at keeping up your own nomenclature and there will be no numbers after P- part).
Filenames are provided as command line arguments, can be typed one by one or used with wildcard as I've shown here. Then we read in the new number from user interactively, and stick that new number for each cropped filename.

$ ls
16115P-barfoo.h  16115P-foobar.c  16115P-foobar.md  updateNames.sh*
$ ./updateNames.sh 16115*                                                                                                        
Enter new number for all specified files: 
17121
17121P-barfoo.h
17121P-foobar.c
17121P-foobar.md
$ cat updateNames.sh                                                                                                             
#!/bin/bash

if [ $# -eq 0  ]; 
then
    echo "<<< Error: no arguments provided"
    exit 1
fi

echo "Enter new number for all specified files: " 
read NEWNUMBER
for file in "$@";
do
  BASE="$(echo "$file" | awk -F '-' '{ gsub( /[[:digit:]]/,""); print }')"
  echo $NEWNUMBER""$BASE
  # uncomment this line for actual copying
  # cp "$file" $NEWNUMBER""$BASE
done

$