[SOLVED] Bash script help on syntax

GPGAgent · 11-25-2018, 08:48 AM

Hi Folks, Yet another very simple bash script syntax bit of help needed.

Before I ask just to let you know I've been programming since 1970, BASIC, Fortran, JCL, ADABAS/Natural, PRO-IV, Javascript, HTML, Coldfusion, SQL and now I'm using bash.

It's got great syntax, nice and concise, and i follow the principles, but some of the probably more obvious sides of it escape me - old age??? maybe, maybe not.

Any way I have folder full of mp4 files.

Code:

onk@XEON4 ~/TEST/700k $ ls -al
total 1777376
drwxrwxr-x 2 onk onk     32768 Nov 22 23:25 .
drwxrwxr-x 7 onk onk    430080 Nov 23 14:50 ..
-rw-rw-r-- 1 onk onk   5680963 Jun 23 19:15 10013.mp4
-rw-rw-r-- 1 onk onk   4640217 Jun 23 19:16 10125.mp4
-rw-rw-r-- 1 onk onk   5866973 Jun 23 19:17 10323.mp4

I have a bash executable that displays WxH

Code:

onk@XEON4 ~/TEST/700k $ VWxH.sh 10013.mp4
512x384


onk@XEON4 ~/TEST/700k $ for i in *.mp4; do echo $i VWxH.sh $i ;done
10013.mp4 VWxH.sh 10013.mp4
10125.mp4 VWxH.sh 10125.mp4
10323.mp4 VWxH.sh 10323.mp4

How do I get it to display the mp4's WxH in a for loop?

I guess I could update VHxH.sh to the filename as well as the video dimensions but I really want to know how to wriet the for loop.

This is VWxH.SH

Code:

#!/bin/bash
exiftool -Imagesize -s3 $1

Cheers

lougavulin · 11-25-2018, 09:09 AM

Missing a semi-coma :

Code:

for i in *.mp4; do echo $i; VWxH.sh $i ;done

lougavulin · 11-25-2018, 09:26 AM

Just a tip, maybe.
When you are writing loop in a terminal, you can start it :

Code:

for i in *.mp4; do

Hit <enter>, it will show you did not end your command by adding '>' and continue :

Code:

> echo $i

Hit <enter> again :

Code:

> VWxH.sh $i

Hit <enter> again :

Code:

> done

Hit <enter>, and then, as this is the end of your loop, it will run it.

pan64 · 11-25-2018, 10:48 AM

In general:
if you want to check how your script actually working: add set -xv at the beginning of your script
if you wish to check the syntax of your script use shellcheck (www.shellcheck.net).

GPGAgent · 11-25-2018, 12:24 PM

Quote:

Originally Posted by lougavulin

Missing a semi-coma :

Code:

for i in *.mp4; do echo $i; VWxH.sh $i ;done

Thanks for that, it's close, but not close enough.

Code:

onk@XEON4 ~/TEST/700k $ for i in *.mp4; do echo $i; VWxH.sh $i ;done
10013.mp4
512x384
10125.mp4
384x288
10323.mp4
512x384
10595.mp4
512x384

I don't wnat a cr/fl after the mp4 name, I want this:

Code:

10013.mp4  512x384
10125.mp4  384x288
10323.mp4  512x384
10595.mp4  512x384

And then I would like to rename the file to this:

Code:

10013-512x384.mp4
10125-384x288.mp4
10323-512x384.mp4
10595-512x384.mp4

cheers

GPGAgent · 11-25-2018, 12:25 PM

Quote:

Originally Posted by pan64

In general:
if you want to check how your script actually working: add set -xv at the beginning of your script
if you wish to check the syntax of your script use shellcheck (www.shellcheck.net).

Great tip, I'll try it out. Thanks

scasey · 11-25-2018, 12:29 PM

see man echo

Code:

-n     do not output the trailing newline

pan64 · 11-25-2018, 12:44 PM

echo is a bash built-in I think. but anyway, echo -n works. Also you can use printf.

GPGAgent · 11-25-2018, 12:46 PM

Quote:

Originally Posted by scasey

see man echo

Code:

-n     do not output the trailing newline

Cheers, man echo should have been my friend

Code:

onk@XEON4 ~/TEST/700k $ for i in *.mp4; do echo -n $i "  " ; VWxH.sh $i ;done
10013.mp4   512x384
10125.mp4   384x288
10323.mp4   512x384

GPGAgent · 11-25-2018, 12:51 PM

So final challenge, using this script so far I would like to mv the fule to a new name w=that includes the WxH

Code:

for i in *.mp4; do echo -n $i "  " ; VWxH.sh $i ;done

New file names

Code:

10013-512x384.mp4   
10125-384x288.mp4   
10323-512x384.mp4   
   or
512x384-10013.mp4   
384x288-10125.mp4   
512x384-10323.mp4

pan64 · 11-25-2018, 01:10 PM

use something like this inside the for loop:

Code:

s=$(VWxH.sh $i)
mv ${i%.mp4} $s-$i

GPGAgent · 11-25-2018, 05:13 PM

Quote:

Originally Posted by pan64

use something like this inside the for loop:

Code:

s=$(VWxH.sh $i)
mv ${i%.mp4} $s-$i

Thanks, just what I've been trying but the syntax is getting to me

Code:

onk@XEON4 ~/STUFF/VIDS/TEST $ for i in *.mp4; do echo -n $i "  " ; VWxH.sh $i ;s=$(VWxH.sh $i);mv ${i%.mp4} $s-$i;  done
1467021_hq.mp4   600x480
mv: cannot stat '1467021_hq': No such file or directory
1684525_hq.mp4   720x480
mv: cannot stat '1684525_hq': No such file or directory
1696132_hq.mp4   1280x720
mv: cannot stat '1696132_hq': No such file or directory
18606_hq.mp4   1280x720
mv: cannot stat '18606_hq': No such file or directory
19586_hq.mp4   640x480
mv: cannot stat '19586_hq': No such file or directory
onk@XEON4 ~/STUFF/VIDS/TEST $ ls -al
total 248244
drwxrwxr-x  2 onk onk     4096 Nov 25 14:55 .
drwxrwxr-x 10 onk onk   323584 Nov 25 18:56 ..
-rw-rw-r--  1 onk onk 25950908 Sep 30 18:49 1467021_hq.mp4
-rw-rw-r--  1 onk onk 52623483 Sep 30 19:20 1684525_hq.mp4
-rw-rw-r--  1 onk onk 88912589 Sep 30 19:18 1696132_hq.mp4
-rw-rw-r--  1 onk onk 72904313 Sep 30 18:54 18606_hq.mp4
-rw-rw-r--  1 onk onk 13403523 Sep 30 17:27 19586_hq.mp4
onk@XEON4 ~/STUFF/VIDS/TEST $ 
onk@XEON4 ~/STUFF/VIDS/TEST $ for i in *.mp4; do echo -n $i "  " ; VWxH.sh $i ;  done
1467021_hq.mp4   600x480
1684525_hq.mp4   720x480
1696132_hq.mp4   1280x720
18606_hq.mp4   1280x720
19586_hq.mp4   640x480
onk@XEON4 ~/STUFF/VIDS/TEST $

michaelk · 11-25-2018, 05:34 PM

Code:

${i%.mp4}

Basically that strips .mp4 from your filename which is not what you want. Instead try

Code:

mv $i $s-$i

This might make it easier.

Code:

#!/bin/bash

for i in *.mp4; do 
    s=$(VWxH.sh $i)
    echo "$i $s"
    mv $i $s-$i
done

I assume you are using a test directory of your files just in case?

pan64 · 11-26-2018, 01:12 AM

you might want to use ", like this:

Code:

mv "${i%.mp4}" "${s}-${i}"

also please try set -xv as it was mentioned, you will see what's happening (and probably post the result and we will explain)
also you can add echo before mv to check the script (and remove echo if that was ok)

GPGAgent · 11-26-2018, 08:22 AM

Thanks pan64 and michaelk, those tips helped

Code:

onk@XEON4 ~/STUFF/VIDS/TEST $ for i in *.mp4; do echo -n $i "  " ; VWxH.sh $i ;cp $i $(VWxH.sh $i)-$i;  done
1467021_hq.mp4   600x480
1684525_hq.mp4   720x480
1696132_hq.mp4   1280x720
18606_hq.mp4   1280x720
19586_hq.mp4   640x480
onk@XEON4 ~/STUFF/VIDS/TEST $ for i in *.mp4; do echo -n $i "  " ; VWxH.sh $i ;cp $i $i-$(VWxH.sh $i);  done
1280x720-1696132_hq.mp4   1280x720
1280x720-18606_hq.mp4   1280x720
1467021_hq.mp4   600x480
1684525_hq.mp4   720x480
1696132_hq.mp4   1280x720
18606_hq.mp4   1280x720
19586_hq.mp4   640x480
600x480-1467021_hq.mp4   600x480
640x480-19586_hq.mp4   640x480
720x480-1684525_hq.mp4   720x480
onk@XEON4 ~/STUFF/VIDS/TEST $

I used cp and not mv, just in case, and it's all good now

The options in the final script will allow for moving or copying, in the same folder or to another folder, and if you precede or follow with the video size.

Many thanks folks

Now solved and I'll be using set -xv as well :-)