for loop vs find 5

[razalas]

Can anyone offer reasons to prefer using find vs using a for loop to process files in a script?

In other words, which of the options below is better?

find

find . -name "*.ext" -exec do_something {} \;

versus

for loop

for file in *.ext
do
   do_something $file
done

Code what you mean,
and mean what you code!
But by all means post your code!

Razalas

 

[elgrandeperro]

find can traverse a whole directory tree, for loops do not.

 

[razalas]

EGP,

good point. I hadn't thought of that.

Thanks!

Code what you mean,
and mean what you code!
But by all means post your code!

Razalas

 

[columb]

To enlarge on elgrandeperro's point I would say that the guideline is use the for construct unless you want to traverse the directory structure.

Note that the -exec parameter to find opens a new process for each file found - as does your for loop so, for functions that take multiple files the options are

find . -name "*.exe" | xargs do_something

and

do_something *.exe

On the internet no one knows you're a dog

Columb Healy

 

[feherke]

Hi

Personally I prefer [tt]find[/tt] because it is much more configurable. For example if I want to process only regular files, with [tt]find[/tt] is just one more switch, but with [tt]for[/tt] I have to add a new command :

find . [red]-type f[/red] -name "*.ext" -exec do_something {} \;

for file in *.ext
do
   [red][ -f "$file" ] || continue[/red]
   do_something $file
done

Additionally, if there is no file matching the *.ext wildcard, then [tt]find[/tt] will generate no output, while [tt]for[/tt]'s behavior depends on the shell's setting ( [tt]shopt[/tt] [tt]nullglob[/tt] in [tt]bash[/tt] ).

Feherke.

http://rootshell.be/~feherke/

 

[stefanwagner]

If you use + instead of \; , find will not start a new process for each match.

find . -name "*.ext" -exec do_something {} +

using -execdir is often useful (will execute the command in the containing directory).
For deletion there is even a shortcut:

find . -name "*.ext" -delete

Yes, talking about gnu/find:

find --version
GNU find Version 4.2.32
Built using GNU gnulib version 8e128ebf42e16c8631f971a68f188c30962818be
Aktivierte Funktionen: D_TYPE O_NOFOLLOW(enabled) LEAF_OPTIMISATION

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[RobJordan]

You could also combine the two in a shell script.

find . -name "*.ext"|while read RECORD
do
echo $RECORD
# you could also manipulate the record here or run other commands
done

Rob

Rob Jordan

http://www.linkedin.com/in/robjordan

 

[stefanwagner]

And some commands don't need neither for, nor find, but process multiple files by themself.

Example: cat foo*

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