[SOLVED] Bash Shell Scripting rename files

pomico · 06-29-2012, 11:49 AM

Hi, I'm trying to write a script that reads in files with a .dat extension, runs them through a program I've already written, and outputs them with a .txt extension.

So far I have:
for file in *dat; do
echo "Reddening $file"
./redden.out < $file > $file.txt
done

which of course leaves me with files appended with .dat.txt.
How can I either get the script to output .txt extensions in the first place, or rename .dat.txt to just .txt?

I have found examples using basename but I'm not sure how to get that to work in this instance.

Since I am completely new to bash, could you please also explain in answers what the terms you use actually do? That's another problem I'm having by looking at similar questions - I don't know what things actually mean so can't figure out how to apply them to my problem.

Thanks a lot!

sag47 · 06-29-2012, 12:08 PM

man bash

See the section on Parameter Expansion.

Code:

file=somefile.dat
echo ${file/.dat/.txt}

ShadowCat8 · 06-29-2012, 12:16 PM

Greetings,

Well, there's a couple ways you can do this... First that comes to mind is as follows:

Code:

#!/bin/bash
#
#

# We should be launching this from the directory the files are in.
# 
for files in `ls -1 *dat`
     do
     echo "Reddening ${files}"
     filename="`echo ${files} | cut -d. -f1`"
     redden.out < ${filename}.dat > ${filename}.txt
     done

#
## EOF

Only real difference is I am grabbing the name of the file, without the extension, in filename using the 'cut' command, using the period ('.') as a delimiter and grabbing the first field. Then use that for the name for both the input to and output from your other program.

Dafydd · 06-29-2012, 08:59 PM

Code:

do
  if [ -f "$filename" ]
    then

	 CAPTION=${filename%.*}

Then write it out to "$CAPTION.txt"

Dafydd · 06-29-2012, 09:01 PM

Let me know what grade your teacher gives me.

ntubski · 06-30-2012, 10:02 AM

Quote:

Originally Posted by ShadowCat8

for files in `ls -1 *dat`

Don't parse ls. The OP had for file in *dat which was perfectly fine (although you may want *.dat).

Quote:

Originally Posted by pomico

I have found examples using basename but I'm not sure how to get that to work in this instance.

basename is for removing directories from a path, not file extensions.

pomico · 07-02-2012, 04:05 AM

Quote:

Originally Posted by Dafydd

Let me know what grade your teacher gives me.

Sorry, was that directed at me?
I'm not taking a class, I am a postgraduate physics student and have been running a series of jobs on the group's supercomputer. I have a couple of programs to run on the data I get out at the end that I have written myself and since there are a number of different data files I thought I would use the opportunity to learn some scripting.
I really do appreciate any help and understand that people use these forums for assignments, but I would appreciate it if you did not jump to conclusions when people such as myself come with genuine beginners problems.

Thanks to everyone for your suggestions, I'll give them a go.

pomico · 07-02-2012, 04:42 AM

Quote:

Originally Posted by ShadowCat8

Greetings,

Well, there's a couple ways you can do this... First that comes to mind is as follows:

Code:

#!/bin/bash
#
#

# We should be launching this from the directory the files are in.
# 
for files in `ls -1 *dat`
     do
     echo "Reddening ${files}"
     filename="`echo ${files} | cut -d. -f1`"
     redden.out < ${filename}.dat > ${filename}.txt
     done

#
## EOF

Only real difference is I am grabbing the name of the file, without the extension, in filename using the 'cut' command, using the period ('.') as a delimiter and grabbing the first field. Then use that for the name for both the input to and output from your other program.

I just tried this, exactly as above, but I get a couple of errors, saying "cut: [-cf] list: illegal list value" followed by " .dat: No such file or directory". From the latter presumably the first field isn't being grabbed?

pomico · 07-02-2012, 04:46 AM

Edit: All working now, the problem was down to me

(as I expected it would be...)

Thanks again!

Dafydd · 07-02-2012, 01:32 PM

Quote:

Originally Posted by pomico

Sorry, was that directed at me?

I owe you an apology. The fact that this was a first post plus the nature of you question, looked very much like a lot of others who were wanting us to do their home work.

I am sorry.
Dave