Bash script to rename files from a text file source

bashrenamescriptingshell

I'm fairly new to bash; I can just about perform simple administrative tasks with simple commands 1 at a time. However, I've been tasked with renaming some files in a directory using a text file as the source for my renaming and would really appreciate a few pointers, as I am well out of my depth.

Let me explain:

New File Name.xlsx 0.1  000011F4.dat 
New File Name.xlsx 0.2  000011F5.dat 
New File Name.xlsx 0.3  000011F6.dat 
New File Name.xlsx 0.4  000011F7.dat 
New File Name.xlsx 0.5  000011F8.dat 
New File Name.xlsx 0.6  000011F9.dat

The source text file I have resembles the above somewhat. The intention is that the first 'column' is the new name for the file, the middle is the version and the third is the current filename.

I need to rename the .dat files in the directory, changing them to the names presented in the first column. I also need to prepend the version number 0.1, 0.2 etc… to the beginning of each file.

I have a few questions:

Is it a massive problem that the files have whitespace in them? Would it be better adding " " around each file string?

Basically I have no idea where to start and any help would be massively appreciated. As you can see it's slightly more complex than a usual renaming, giving the need to add the version column to the beginning of the filename and the whitespace in the list.

Best Answer

This ought to work:

sh <(sed -r 's/^\s*(.*)\s+([0-9\.]+)\s+([0-9A-Z]{8}\.dat)\s*$/mv -iv \3 "\2 \1"/' files)

... where files is the name of your source file.

What this does is pass the result of the sed command to a new instance of sh (the shell), using process substitution. The output of the sed command is:

mv -iv 000011F4.dat "0.1 New File Name.xlsx"
mv -iv 000011F5.dat "0.2 New File Name.xlsx"
mv -iv 000011F6.dat "0.3 New File Name.xlsx"
mv -iv 000011F7.dat "0.4 New File Name.xlsx"
mv -iv 000011F8.dat "0.5 New File Name.xlsx"
mv -iv 000011F9.dat "0.6 New File Name.xlsx"

Taking the sed command apart, it searches for a pattern:

^ - the beginning of the line
\s* - any whitespace at the start
(.*) - any characters (the parentheses store the result to \1)
\s+ - at least one whitespace character
([0-9\.]+) - at least one of 0-9 and . (stored to \2)
\s+ - at least one whitespace character
([0-9A-Z]{8}\.dat) - 8 characters in 0-9 or A-Z, followed by .dat (stored to \3)
\s* - any whitespace at the end
$ - the end of the line

... and replaces it with mv -iv \3 "\2 \1", where \1 to \3 are the previously stored values. You can use something other than a space between the version number and the rest of the filename, if you like.

Here's the result:

$ ls -l
total 60
-rw-rw-r-- 1 z z   0 Aug  8 14:15 000011F4.dat
-rw-rw-r-- 1 z z   0 Aug  8 14:15 000011F5.dat
-rw-rw-r-- 1 z z   0 Aug  8 14:15 000011F6.dat
-rw-rw-r-- 1 z z   0 Aug  8 14:15 000011F7.dat
-rw-rw-r-- 1 z z   0 Aug  8 14:15 000011F8.dat
-rw-rw-r-- 1 z z   0 Aug  8 14:15 000011F9.dat
-rw-rw-r-- 1 z z 222 Aug  8 13:47 files
$ sh <(sed -r 's/^\s*(.*)\s+([0-9\.]+)\s+([0-9A-Z]{8}\.dat)\s*$/mv -iv \3 "\2 \1"/' files)
`000011F4.dat' -> `0.1 New File Name.xlsx'
`000011F5.dat' -> `0.2 New File Name.xlsx'
`000011F6.dat' -> `0.3 New File Name.xlsx'
`000011F7.dat' -> `0.4 New File Name.xlsx'
`000011F8.dat' -> `0.5 New File Name.xlsx'
`000011F9.dat' -> `0.6 New File Name.xlsx'
$ ls -l
total 60
-rw-rw-r-- 1 z z   0 Aug  8 14:15 0.1 New File Name.xlsx
-rw-rw-r-- 1 z z   0 Aug  8 14:15 0.2 New File Name.xlsx
-rw-rw-r-- 1 z z   0 Aug  8 14:15 0.3 New File Name.xlsx
-rw-rw-r-- 1 z z   0 Aug  8 14:15 0.4 New File Name.xlsx
-rw-rw-r-- 1 z z   0 Aug  8 14:15 0.5 New File Name.xlsx
-rw-rw-r-- 1 z z   0 Aug  8 14:15 0.6 New File Name.xlsx
-rw-rw-r-- 1 z z 222 Aug  8 13:47 files

Related Solutions

Bash – Read non-bash variables from a file into bash script

While you can transform this file to be a shell snippet, it's tricky. You need to make sure that all shell special characters are properly quoted.

The easiest way to do that is to put single quotes around the value and replace single quotes inside the value by '\''. You can then put the result into a temporary file and source that file.

script=$(mktemp)
sed <"config-file" >"$script" \
  -e '/^[A-Z_a-z][A-Z_a-z]*=/ !d' \
  -e s/\'/\'\\\\\'\'/g \
  -e s/=/=\'/ -e s/\$/\'/

I recommend doing the parsing directly in the shell instead. The complexity of the code is about the same, but there are two major benefits: you avoid the need for a temporary file, and the risk that you accidentally got the quoting wrong and end up executing a part of a line as a shell snippet (something like dangerous='$(run me)'). You also get a better chance at validating potential errors.

while IFS= read -r line; do
  line=${line%%#*}  # strip comment (if any)
  case $line in
    *=*)
      var=${line%%=*}
      case $var in
        *[!A-Z_a-z]*)
          echo "Warning: invalid variable name $var ignored" >&2
          continue;;
      esac
      if eval '[ -n "${'$var'+1}" ]'; then
        echo "Warning: variable $var already set, redefinition ignored" >&2
        continue
      fi
      line=${line#*=}
      eval $var='"$line"'
  esac
done <"config-file"

Bash – Add text to end of the filename but before extension

The answer that you looked at was for a question that did not ask for the actual renaming of files on disk, but just to transform the names of the files as reported on the terminal.

This means that you solution will work if you use the mv command instead of printf (which will just print the string to the terminal).

for f in *.mp3; do mv "$f" "${f%.mp3}_p192.mp3"; done

I'd still advise you to run the the printf loop first to make sure that the names are transformed in the way that you'd expect.

It is often safe to just insert echo in front of the mv to see what would have been executed (it may be a good idea to do this when you're dealing with loops over potentially destructive command such as mv, cp and rm):

for f in *.mp3; do echo mv "$f" "${f%.mp3}_p192.mp3"; done

or, with nicer formatting:

for f in *.mp3; do
    echo mv "$f" "${f%.mp3}_p192.mp3"
done

Best Answer

Related Solutions

Bash – Read non-bash variables from a file into bash script

Bash – Add text to end of the filename but before extension

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