Bash How reuse found files name?

Question

I want to run a script in a directory in order to generate an svg file for each found dot file. Something like:

find . -name "*.dot" -exec dot -Tsvg \{} \;

This works fine but just output the result on stdout. usually I am using a redirection to generate the svg file. How can I get the dot file name to use it in the redirection like

find . -name "*.dot" -exec dot -Tsvg > "$dotfilename".svg \{} \;

score 5 · Accepted Answer · edited May 23 '17 at 12:29

5

The following:

for i in `find . -name "*.dot"`; do
   dot -Tsvg $i > $i.svg
done

performs the find (in backticks) and loops over the results, executing dot for each one. The filename is in $i.

This uses backtick substitution and is a useful mechanism for capturing command output for subsequent use in another command.

To remove the extension and add another, use ${i%.*}.svg. See this SO answer for more info.

edited May 23 '17 at 12:29

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answered Jul 12 '12 at 14:30

Brian Agnew

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Many thanks. In addition is it easily possible to remove the .dot extension from the svg file ? – Manuel Selva Jul 12 '12 at 14:32
Granted. Has some limitations – Brian Agnew Jul 12 '12 at 14:36

chepner · Answer 2 · 2012-07-12T16:05:28.333

You don't need output redirection. Use -O to save to a file whose name is automatically created from the input file name and the output format.

find . -name "*.dot" -exec dot -Tsvg -O \{} \;

Just to point out that you can use {} multiple times in the argument to -exec:

find . -name "*.dot" -exec dot -Tsvg -o \{}.svg \{} \;

Where the first would produce "foo.svg" from "foo.dot", the second would produce "foo.dot.svg"

score 2 · Answer 3 · answered Jul 12 '12 at 14:31

2

You can't do the redirection here. find does execute using execvp(3) or friends, not the shell. Instead, use shell globs, or make a script which you then can call from find

An example:

for i in ./*.dot
do
    svg=${i%.dot}.svg
    dot -Tsvg "$i" > "$svg"
done

answered Jul 12 '12 at 14:31

Jo So

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In bash v4 you can use globstar to get recursion from the glob. – jordanm Jul 12 '12 at 14:37
Yah. I don't want that crap (apart from the fact that it depends on bash). I prefer fixing my file organization should there ever be need. – Jo So Jul 12 '12 at 14:46

score 2 · Answer 4 · answered Jul 12 '12 at 14:36

The problem that you are having is that redirection is processed before the find command. You can work around this by spawning another bash process in the -exec call. This also makes it easy to remove the extension using parameter expansion.

find . -name "*.dot" -exec bash -c 'dot -Tsvg "$1" > "${1%.*}".svg' -- {} \;

Bash How reuse found files name?

4 Answers4