[SOLVED] Returning TAR_FD to tar in bash script

[Paddy Landau]

I wish to automate tar with multi-volume spanning. For that, I need a script.

The following link gives a script written in sh (using #!/bin/sh)
http://www.gnu.org/software/tar/manual/html_node/Multi_002dVolume-Archives.html#SEC156

The script works, but I need to modify this script a little. However, I'm totally unfamiliar with sh, and I'm familiar with bash. Thus, I've rewritten this in bash (using #!/bin/bash).

But...

The sh script sets TAR_FD as:

echo ${name:-$TAR_ARCHIVE}-$TAR_VOLUME >&$TAR_FDThe equivalent in bash, I thought, was:

TAR_FD=${NEWNAME}(where ${NEWNAME} contains the new name)

However, tar doesn't receive this new name and continues to reuse the old name.

I've also tried

export TAR_FD=${NEWNAME}without success.

How do I return TAR_FD back to tar?

Thanks.

[Paddy Landau]

Doh! I've answered my own question.

TAR_FD is a file descriptor. The answer is the same as for sh:

echo ${NEWNAME} >&${TAR_FD}

[scorp123]

The following link gives a script written in sh (using #!/bin/sh)
http://www.gnu.org/software/tar/manual/html_node/Multi_002dVolume-Archives.html#SEC156

The script works, but I need to modify this script a little. However, I'm totally unfamiliar with sh, and I'm familiar with bash. I was under the impression that /bin/sh and /bin/bash are one and the same on Linux?

Ubuntu uses a "light-weight" version called "dash" per default, but "dash" should be 100% compatible to "bash". I have seen a few rare cases though where for some odd reason a script did not function as intended. In that case you'd have to disable "dash" and reroute "/bin/sh" to "bash" again. In a shell, please type this:

sudo dpkg-reconfigure dash When asked if you want to use "dash" as "/bin/sh" say "No" and it will reroute it back to "bash" again. Before that change becomes active you will have to logout and login back again.

[Paddy Landau]

I was under the impression that /bin/sh and /bin/bash are one and the same on Linux?
Well, I'm not exactly an expert, so I go by the fact that they have different manuals (man sh and man bash), and that I don't understand the sh script.

Thanks for the ideas. I have it working now.

[scorp123]

man sh and man bash For me the two open the same thing: bash's manual ...

[Paddy Landau]

For me the two open the same thing: bash's manual ...
I'm guessing that's because you did what you described:


sudo dpkg-reconfigure dash When asked if you want to use "dash" as "/bin/sh" say "No" and it will reroute it back to "bash" again.
My man bash and man sh are definitely different. Briefly looking at the two manuals, I notice that they look mostly the same.