How to rename file name contains backslash in bash?

I got a tar file, after extracting, there are many files naming like

a
bc
def
gh

I want to correct their name into files in sub-directories like

a
b/c
d/e/f
g/h

I face a problem when a variable contains backslash, it will change the original file name. I want to write a script to rename them.

Answer

Parameter expansion is the way to go. You have everything you need in bash, no need to use external tools like find.

$ touch a\b c\d\e
$ ls -l
total 0
-rw-r--r--  1 ghoti  staff  0 11 Jun 23:13 ab
-rw-r--r--  1 ghoti  staff  0 11 Jun 23:13 cde
$ for file in *\*; do
> target="${file//\//}"; mkdir -p "${target%/*}"; mv -v "$file" "$target"; done
ab -> a/b
cde -> c/d/e

The for loop breaks out as follows:

• for file in *\*; do – select all files whose names contain backslashes
• target="${file//\//}"; – swap backslashes for forward slashes
• mkdir -p "${target%/*}"; – create the target directory by stripping the filename from $target
• mv -v "$file" "$target"; – move the file to its new home
• done – end the loop.

The only tricky bit here I think is the second line: ${file//\//} is an expression of ${var//pattern/replacement}, where the pattern is an escaped backslash (\) and the replacement is a single forward slash.

Have a look at man bash and search for “Parameter Expansion” to learn more about this.

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Alternately, if you really want to use find, you can still take advantage of bash’s Parameter Expansion:

find . -name '*\*' -type f 
  -exec bash -c 't="${0//\//}"; mkdir -p "${t%/*}"; mv -v "$0" "$t"' {} ;

This uses find to identify each file and process it with an -exec option that basically does the same thing as the for loop above. One significant difference here is that find will traverse subdirectories (limited by the -maxdepth option), so … be careful.