how can I rename multiple files by inserting a character?

Question

I have many files of the form

sw001
sw002
sw003
...

I want to insert a period between the sw's and the number values. How can I accomplish this?

score 8 · Answer 1 · answered Mar 02 '12 at 18:37

8

If you don't have rename and don't feel like downloading it, use this:

for file in sw*; do
    mv "$file" "${file/sw/sw.}"
done

answered Mar 02 '12 at 18:37

Kevin

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Be aware that the pattern substitution `${file/sw/sw.}"` also matches files like `FOOsw001`. Besides - this kind of substitution is not supported by all shells. Removing a prefix pattern should be more appropriate and portable: `"$sw.{file#sw}"` – maxschlepzig Mar 02 '12 at 19:16
2

@maxschlepzig I suppose it would, but because of the glob all names it encounters necessarily begin with `sw`. Good to point out in general though. – Kevin Mar 02 '12 at 19:20

score 5 · Accepted Answer · edited Mar 02 '12 at 23:02

5

On Linux:

rename 'sw' 'sw.' sw*

On Debian, Ubuntu and derivatives, use rename.ul instead of rename (rename is a different file renaming command on those distributions).

edited Mar 02 '12 at 23:02

Gilles 'SO- stop being evil'

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answered Mar 02 '12 at 18:12

rsaw

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Whups. Wrong link. :( – Daniel Pittman Mar 02 '12 at 18:14
@Daniel: What do you mean "wrong link"? – rsaw Mar 02 '12 at 18:17
I edited my comment - apparently there *is* a second utility by the name `rename` out there. Which is awesome. I linked to the wrong manual page, but didn't notice because they are close enough... – Daniel Pittman Mar 02 '12 at 18:19
Gotcha. It's interesting that you say the perl rename is usually the default -- I've never run into it before at all. As you say, the rename I'm familiar with should be on most linux boxen, shipping with util-linux. – rsaw Mar 02 '12 at 18:47
I am as surprised as you are, in the opposite direction. :) – Daniel Pittman Mar 02 '12 at 19:05
@ryran Debian and derivatives ship a different utility under the name `rename`. – Gilles 'SO- stop being evil' Mar 02 '12 at 23:03
Ahhh. I use Ubuntu occasionally but I guess I had never noticed. Thanks for the explanation ... and edit .. @Gilles. – rsaw Mar 03 '12 at 07:20

Daniel Pittman · Answer 3 · 2012-03-02T18:17:39.013

1

If you can can express the transformation as a Perl regular expression, rename that ships with Perl is a great choice. It applies a Perl expression to each filename, then changes the name if it is different. Often, a Perl regular expression substitution is what you want:

rename 's/sw/sw./' sw*

This is different from the rename(1) that ships with util-linux-ng, but normally the Perl version is the default. See man 1 rename to check which one your system has.

edited Mar 02 '12 at 18:17

answered Mar 02 '12 at 18:07

Daniel Pittman

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Can you help me to understand what the / notation means? – Paul Mar 02 '12 at 18:09
Hopefully that edit is clearer: the man page was for a different utility with the same name, and I didn't notice because it was close enough. The Perl rename applies a Perl expression; 's///' is a regular expression substitution. – Daniel Pittman Mar 02 '12 at 18:18
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If this `rename` expression is indeed a regular expression, the `.` character would mean "any one character", so it should be escaped in order to be taken literally. – Mar 02 '12 at 18:45
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@hesse, it would in the match part, not in the replacement part. :) – Daniel Pittman Mar 02 '12 at 19:05
The Perl version is the default in Debian and derivatives including Ubuntu. It's not shipped by other distributions. – Gilles 'SO- stop being evil' Mar 02 '12 at 23:01

how can I rename multiple files by inserting a character?

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