[Shell Scripting] How do I loop through files...

[mOOse]

How would I loop through all the files in a given directory (passed at the command prompt) and then do something to each of those files.

for i in *; do

echo $i;
done

For example, the above will loop through all the files in the current directory. I need to just loop through the passed directory. I've tried piping it through a "find dirname -maxdepth 1 -type f" command but then the variables inside the loop get reset to 0 upon exiting the loop for some inexplicable reason. Any suggestions?

[Bradmont]

You can do it this way:


#!/bin/bash

if [ $# -ne 1 ] ;
echo "usage: $0 <directory>" >&2
fi

for file in $1/*; do
echo $file; # or whatever you want to do
done


I've used a couple built-in variables here, they are:

$# -- The number of command line arguments
$0 -- The name of the script (It's grabbed from the command line, so if the script's invoked as "./foo eat a pie", $0 will be "./foo")
$1 -- the first command line argument, "eat" from the above example($2, $3, $4, etc, will be the 2nd, 3rd and 4th)

<edit> I need to larn two speel </edit>

[mOOse]

Thank You! That's exactly what I wanted. Another quick question, how would I make the above code work recursivly through the directory passed. I guess I could put
for file in $1/* $1/*/* $1/*/*/*; etc but I know there has to be a better way.

[Bradmont]

here's a nice little example of recursion, it should be pretty easy to adapt to what you want:

http://tldp.org/LDP/abs/html/localvar.html#EX63

However, that might not be the best solution -- instead you could use find, and do something like this:

for file in `find $1`; do ... done

that'll give you the names of all the files in $1 and all its subdirectories.

[bwkaz]

for i in $(find $1 -type f) ; do
echo $i
doneSomething like that?

[GnuVince]

mOOse: You could always use a more powerful scripting language:

Ruby:

require "find"

Find.find("/path") { |file|
system("echo #{file}")
}


bwkaz's way should work too

[mOOse]

Thank you all, you've been great help.

would ask questions again A+++++++++++++ :)

ps I've made a small donation to help support this place

[inkedmn]

you could do it in python too:


import os

for file in os.listdir("your path here"):
print file,


[edit]
didn't notice you wanted it to be recursive/check subdirectories. python has a method called os.path.walk(), you can see a basic example of it here (http://www.inkedmn.net/code/walktest.py).