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How can I bulk replace the prefix for many files?

I have a lot of files like

  • TestSRConnectionContext.h
  • TestSRConnectionContext.m

I would like to change all them to

  • CLConnectionContext.h
  • CLConnectionContext.m

How would I do this?

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up vote 18 down vote accepted
for name in TestSR*
    newname=CL"$(echo "$name" | cut -c7-)"
    mv "$name" "$newname"

This uses bash command substitution to remove the first 6 characters from the input filename via cut, prepends CL to the result, and stores that in $newname. Then it renames the old name to the new name. This is performed on every file.

cut -c7- specifies that only characters after index 7 should be returned from the input. 7- is a range starting at index 7 with no end; that is, until the end of the line.

Previously, I had used cut -b7-, but -c should be used instead to handle character encodings that could have multiple bytes per character, like UTF-8.

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Thx, i got this right now by myself too. Marking as answer. Thx – ErikTJ Sep 6 '12 at 16:35
This works nicely, thanks. Can you explain what the -b7- does? Is this reference to the byte-list? ss64.com/bash/cut.html – imjared Sep 26 '13 at 16:01
@imjared Updated the answer with more details. – mrb Sep 26 '13 at 17:08

I'd say the simplest it to just use the rename command. See it's man page (it's as simple as it gets) but for changing extensions the following should work just fine:

rename 's/^TestSR/CL/' *

This of course expects you to be on the directory of the files. This will not overwrite files. If you want that, just pass the -f option.

EDIT: see jw013 comment below about multiple versions of rename

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A caveat: multiple versions of rename exist in the wild. Check your local rename documentation to figure out how to use yours. – jw013 Sep 6 '12 at 17:39

Shell parameter expansion is enough for simple transformations like this. Command substitution is less efficient because of the need to spawn extra processes (for the command substitution itself and the cut/sed).

for f in TestSR*; do mv "$f" "CL${f#TestSR}"; done
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Here's one way:

ls *.{h,m} | while read a; do n=CL$(echo $a | sed -e 's/^Test//'); mv $a $n; done
  • ls *.{h,m} --> Find all files with .h or .m extension
  • n=CL --> Add a CL prefix to the file name
  • sed -e 's/^Test//' --> Removes the Test prefix from the file name
  • mv $a $n --> Performs the rename
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You can try with:

for i in TestSR*; do mv ${i} ${i/#TestSR/CL}; done

See man bash (section "Parameter Expansion") for details.

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If you need something more perlish you can do this

perl -e 'for(@ARGV) { rename($_, $n) if( ($n = $_ ) =~ s/^TestSR/CL/) }' *
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Well, it wasn't as hard as i though.

$ for f in TestSR*.m; do mv $f CL$(echo $f | cut -c7-); done;
$ for f in TestSR*.h; do mv $f CL$(echo $f | cut -c7-); done;
share|improve this answer
In case it helps for the future, you don't have to repeat the commands for your two patterns; you can use (for example): for f in TestSR*.[mh], for f in TestSR*.{m,h}, for f in TestSR*.m TestSR*.h. – mrb Sep 6 '12 at 22:37

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