Command runs in Linux terminal but not in bash script

Question

I wanted to automate the process of fixing the indexing on some videos. Below is my code.

for f in ~/Videos/Temp/*
do
    f=$(echo $f | sed 's/ /\\ /g')
    name=$(echo $f | sed 's/Temp/Fixed/1')
    mencoder -forceidx "$f" -o "$name" -oac copy -ovc copy
done

The problem I am having is that mencoder is claiming that it cannot find the file store in the variable $f.

MEncoder svn r34540 (Ubuntu), built with gcc-4.6 (C) 2000-2012 MPlayer Team
File not found: '/home/name/Videos/Temp/file\ name.avi'
Failed to open /home/bryan/Videos/Temp/file\ name.avi.
Cannot open file/device.

Exiting...

When I print the command to the terminal with the expanded variables and run it, it works just fine. I even modified my above code to print out the command for fixing each video, pasted that into a new script, and everything worked without a hitch. I am running this on Ubuntu. Any ideas as to what might cause this?

You don't need to escape your spaces, since you (correctly) use quotes around your variable. Maybe that's (part of?) the problem? You may also want to check that your Terminal is also using bash as it's shell. — mivk
– mivk, Commented May 25, 2012 at 7:35
@mivk: Except that the variable isn't quoted when it's echoed in the assignment to name. Variables should always be quoted when they're expanded (as you know). — Dennis Williamson
– Dennis Williamson, Commented May 25, 2012 at 11:26
What is causing it (as you know) is spaces in the filenames. The best solution is to rename all the files so that they don't contain whitespace. Allowing whitespace in paths is a poor design decision on the part of the filesystem maintainer. Using whitespace in paths is absurd. Demanding that filesystems support them ought to be a capital offense. — William Pursell
– William Pursell, Commented May 25, 2012 at 12:23
@dennis: f=$(echo some file name); touch "$f"; ls "$f"returns some file name. But f2=$(echo $f | sed 's/ /\\ /g'); ls "$f2" returns ls: cannot access some\ file\ name: No such file or directory. (At least with bash 4.1.5.) — mivk
– mivk, Commented Jun 5, 2012 at 22:17

chepner · Accepted Answer · 2012-05-25 13:14:59Z

1

As others have pointed out, you don't need to manually escape the spaces in the file name. However, you don't need to use sed to modify the paths, either.

for f in ~/Videos/Temp/*
do
    mencoder -forceidx "$f" -o "${f/Temp/Fixed}" -oac copy -ovc copy
done

Only the first occurrence of "Temp" is replaced with "Fixed", so you needn't worry about unintended replacements in your file names.

answered May 25, 2012 at 13:14

chepner

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Comments

Wei Liu · Accepted Answer · 2012-05-26 02:37:06Z

0



    find ~/Videos/Temp/ -type f -print0 | while IFS= read -r -d $'\0' f; do
        name=$(echo "$f" | sed 's/Temp/Fixed/1')
        mencoder -forceidx "$f" -o "$name" -oac copy -ovc copy
    done

edited May 26, 2012 at 2:37

answered May 25, 2012 at 7:24

Wei Liu

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3 Comments

Bram Over a year ago

It's probably best to use full paths as well in a script, just in case you want to schedule it later.

Wei Liu Over a year ago

That's true. I do normally convert relative path to full path at the beginning of the script.

Dennis Williamson Over a year ago

$f should be quoted in the second line.

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