Shell script - Two for loops and changing extension of file

Question

Hello all,

I have this Shell script and I've managed to muck it up and I was hoping I could be corrected and put on the right path and hopefully add a few things that I am not competent enough to do myself. I have put what I want do as comments in the Shell script below.

#!/bin/bash
#Get all files from dir "videos" and send to processLine function one at a time
cd /home/test/videos/
for file in `dir -d *` ; do
processLine -f $file
done

processLine(){
# I was hoping to have a further for loop that would loop 4 times and change the $ext
#variable to avi, mpg, wmv and mov
#For loop, execute a command on each file
for i in 1 2 3 4 5 6 7 8 9 10
do
START=$(date +%s.%N)
echo "$line"
#The saved file in done dir should have filename as $file + START.
eval "ffmpeg -i $file -ar 44100 /home/test/videos/done/$fileSTART.$ext" > /dev/null 2>&1

END=$(date +%s.%N)
DIFF=$(echo "$END - $START" | bc)

echo "$line, $START, $END, $DIFF" >> file.csv 2>&1
echo "It took $DIFF seconds"
echo $line
done
}

Basic idea of the script is to: Get all files from dir and run an ffmpeg command on them and see how long it takes. I am trying to collect some stats

Thank you for any help

Update

Making use of Juliano's script and swapping for loops 2 and 3. I have managed to get this output below:

.
.
.
/home/test/videos/done 8 mov took 0.012 seconds
/home/test/videos/done 9 mov took 0.012 seconds
/home/test/videos/video1236104961.flv 0 avi took 0.446 seconds

It pauses there.

Answer 1

1) Where is $line defined?

2) Do you ever use $i?

3) You can loop over extensions via

for ext in avi mov mpg wmv; do
    ffmpg ...
done

4) You can do basic arithmetic in bash with double parens. So $(($x-$y)) instead of piping to bc

Answer 2

Many things are wrong.

1. Don't use dir or ls in for loops.
2. Why eval? What you expected to get?
3. You use $line without defining it.
4. Don't use bc to do math, since bash is already equipped to do it.
5. Don't use date to measure time, bash already provides a command for that.
6. What is "-f" passed to processLine() ?

Another try, fixing some issues:

#!/bin/bash
TIMEFORMAT=%6R
for file in /home/test/videos/* ; do
  if [ ! -f "$file" ]; then
    continue   # anything that is not a regular file
  fi
  for ext in avi mpg wmv mov; do
    for (( i = 0; i < 10; i++ )); do
      base="${file##*/}"
      elapsed=$({ time ffmpeg -i "$file" -ar 44100 -y "${file%/*}/done/${base%.*}-$i.$ext" &>/dev/null; } 2>&1)
      echo "$file $ext $i took $elapsed seconds"
    done
  done
done

Answer 3

I smell a bash pitfall.

$ touch aaa
$ touch "bbb ccc"
$ ls -1
aaa
bbb ccc
$ for file in `dir -d *`; do echo $file; done
aaa
bbb\
ccc