"001" and "0012" converted to "01", "12". How?

stf92 · 07-08-2011, 05:57 PM

Bash 3.1.7

Hi:
I have the following two examples of parameter substitution:

Code:

    old1="${old%:*}"     #strips off everything from the final ":" to the end.  
    old2="${old##*:}"    #strips off everything from the beginning to the final ":".

Now, let me have

Code:

    CONT=1
    while [ 1 ]
    do
         echo FILE"$CONT".txt
         ((CONT = CONT + 1))
    done

That would output
FILE1
FILE2
...
FILE9
FILE10
...

But suppose what I really want the script to output is:
FILE01
FILE02
...
FILE09
FILE10
...

I think the first two examples could help. First, I would do
CONT="00$CONT"
This would give these values for CONT:
001
002
...
009
0010

Next, it is a matter of keeping the last two caracters of CONT and strip the rest off. But how?

Reuti · 07-08-2011, 06:04 PM

There is a command printf which will allow an easy formatting:

Code:

$ printf "FILE%03d\n" 42

sycamorex · 07-08-2011, 06:21 PM

Reuti's solution is nice and clean. I unnecessarily started writing nested while loops

TobiSGD · 07-08-2011, 06:27 PM

+1 to Reuti, hadn't thought that it can be so simple.

Tinkster · 07-08-2011, 06:31 PM

Quote:

Originally Posted by stf92

Bash 3.1.7

Hi:
I have the following two examples of parameter substitution:

Code:

    old1="${old%:*}"     #strips off everything from the final ":" to the end.  
    old2="${old##*:}"    #strips off everything from the beginning to the final ":".

Now, let me have

Code:

    CONT=1
    while [ 1 ]
    do
         echo FILE"$CONT".txt
         ((CONT = CONT + 1))
    done

That would output
FILE1
FILE2
...
FILE9
FILE10
...

But suppose what I really want the script to output is:
FILE01
FILE02
...
FILE09
FILE10
...

I think the first two examples could help. First, I would do
CONT="00$CONT"
This would give these values for CONT:
001
002
...
009
0010

Next, it is a matter of keeping the last two caracters of CONT and strip the rest off. But how?

And an alternative solution:

Code:

for i in {001..099};do echo FILE$i; done

Cheers,
Tink

stf92 · 07-08-2011, 06:37 PM

$ printf "%02d\n" 1
01
$

OK. The 0 after % pads with zeroes. d is the decimal radix spec. Now

$ printf "%02d\n" 012
10
$

012, because of the leading zero, is interpreted in octal! How is this?

@Tinkster: I think I'd give the whole script:

Code:

#!/bin/bash
#                       
#                 
# This script takes a .cue file as input and the corresponding .flac,
# producing a set of .wav files. I suggest to keep the .cue and this 
# file in the same dir. The .cue file is CD5\ Nos.17\,18\,19\,20\,21.cue.
# The .flac is CD5 Nos.17,18,19,20,21.flac.

# WARNING: erase all .wav previously written by this script before running.
#          flac writes the .wav as read only. It it finds a .wav file of
#          the same name from a previous run, it will try to overwrite it.
#          But the file will be read only.

file=$1
infile=$1".cue"
FLACFILE=$1".flac"
FIRST=1
CONT=01

while read A1 A2 A3            # TRACK 08 AUDIO
do
if [ "$A1" == "TRACK" ] 
then 
        read A1 A2             # TITLE "Piano ..........."
        read A1 A2 A3          # INDEX 00 40:18:43 (mm:ss:ff)
                               # We must transform mm:ss:ff into mm:ss.ss
                               # where ss.ss is secons and decimal fraction
        old="$new"
        new="$A3"              # 40:18:43
        if [ $FIRST == 1 ]
        then
                FIRST=0
        else
                old1="${old%:*}"     #strips off everything from the final ":" to the end.
                new1="${new%:*}"
                old2="${old##*:}"    #strips off everything from the beginning to the final ":".
                new2="${new##*:}"
                (("old2 = 10#$old2 * 100 / 75"))      # ff -> ss/75
                (("new2 = 10#$new2 * 100 / 75"))

                old1=$old1"."$old2                    # old1= mm:ss.ss 
                new1=$new1"."$new2

                WAVFILE="$file"$CONT".wav"
                echo "$old1  $new1 $WAVFILE"
#               flac -f --decode --skip=$old1 --until=$new1 -o "$WAVFILE" "$FLACFILE"
                ((CONT = CONT + 1))
        fi
fi

done < "$infile"
WAVFILE="$file"$CONT".wav"
echo "$new1 $WAVFILE"
#flac -f --decode --skip=$new1 -o "$WAVFILE" "$FLACFILE"
exit

Thanks.

sycamorex · 07-08-2011, 06:47 PM

Quote:

Originally Posted by stf92

$ printf "%02d\n" 1
01
$

OK. The 0 after % pads with zeroes. d is the decimal radix spec. Now

$ printf "%02d\n" 012
10
$

012, because of the leading zero, is interpreted in octal! How is this?

Where did you take 012 from? Wouldn't you need:

Code:

printf "FILE%02d\n" "$CONT"

or

Code:

printf "FILE%03d\n" "$CONT"

stf92 · 07-08-2011, 06:55 PM

Yes, that exactly what I would need. And at present I am reading http://www.gnu.org/software/libc/man...rmatted-Output

I know I will find here what I need. The info and man pages for printf merely say it is similar to the C printf function, point out the differences.

EDIT: Here is the full code with due modifications plus its output:

Code:

semoi@darkstar:~/BEETHOVEN/Wilhelm Backhaus - The 32 Beethoven Piano Sonatas/CD5/CD5_done$ cat t18.sh
#!/bin/bash
#                       
#                 
# This script takes a .cue file as input and the corresponding .flac,
# producing a set of .wav files. I suggest to keep the .cue and this 
# file in the same dir. The .cue file is CD5\ Nos.17\,18\,19\,20\,21.cue.
# The .flac is CD5 Nos.17,18,19,20,21.flac.

# WARNING: erase all .wav previously written by this script before running.
#          flac writes the .wav as read only. It it finds a .wav file of
#          the same name from a previous run, it will try to overwrite it.
#          But the file will be read only.

file=$1
infile=$1".cue"
FLACFILE=$1".flac"
FIRST=1
CONT=01

while read A1 A2 A3            # TRACK 08 AUDIO
do
if [ "$A1" == "TRACK" ] 
then 
        read A1 A2             # TITLE "Piano ..........."
        read A1 A2 A3          # INDEX 00 40:18:43 (mm:ss:ff)
                               # We must transform mm:ss:ff into mm:ss.ss
                               # where ss.ss is secons and decimal fraction
        old="$new"
        new="$A3"              # 40:18:43
        if [ $FIRST == 1 ]
        then
                FIRST=0
        else
                old1="${old%:*}"     #strips off everything from the final ":" to the end.
                new1="${new%:*}"
                old2="${old##*:}"    #strips off everything from the beginning to the final ":".
                new2="${new##*:}"
                (("old2 = 10#$old2 * 100 / 75"))      # ff -> ss/75
                (("new2 = 10#$new2 * 100 / 75"))

                old1=$old1"."$old2                    # old1= mm:ss.ss 
                new1=$new1"."$new2

                printf -v CONT2 "%002d" $CONT
                WAVFILE="$file"$CONT2".wav"
                echo "$old1  $new1 $WAVFILE"
#               flac -f --decode --skip=$old1 --until=$new1 -o "$WAVFILE" "$FLACFILE"
                ((CONT = CONT + 1))
        fi
fi

done < "$infile"
printf -v CONT2 "%002d" $CONT
WAVFILE="$file"$CONT2".wav"
echo "$new1 $WAVFILE"
#flac -f --decode --skip=$new1 -o "$WAVFILE" "$FLACFILE"
exit

semoi@darkstar:~/BEETHOVEN/Wilhelm Backhaus - The 32 Beethoven Piano Sonatas/CD5/CD5_done$ ./t18.sh CD5\ Nos.17\,18\,19\,20\,21     
00:00.0  08:28.13 CD5 Nos.17,18,19,20,2101.wav
08:28.13  14:45.26 CD5 Nos.17,18,19,20,2102.wav
14:45.26  21:13.97 CD5 Nos.17,18,19,20,2103.wav
21:13.97  27:35.57 CD5 Nos.17,18,19,20,2104.wav
27:35.57  31:21.33 CD5 Nos.17,18,19,20,2105.wav
31:21.33  35:28.26 CD5 Nos.17,18,19,20,2106.wav
35:28.26  40:18.0 CD5 Nos.17,18,19,20,2107.wav
40:18.0  43:53.40 CD5 Nos.17,18,19,20,2108.wav
43:53.40  47:21.77 CD5 Nos.17,18,19,20,2109.wav
47:21.77  50:27.84 CD5 Nos.17,18,19,20,2110.wav
50:27.84  53:40.97 CD5 Nos.17,18,19,20,2111.wav
53:40.97  62:36.89 CD5 Nos.17,18,19,20,2112.wav
62:36.89  65:53.17 CD5 Nos.17,18,19,20,2113.wav
65:53.17 CD5 Nos.17,18,19,20,2114.wav
semoi@darkstar:~/BEETHOVEN/Wilhelm Backhaus - The 32 Beethoven Piano Sonatas/CD5/CD5_done