Looping through filenames with spaces

KenJackson · #1 (**permalink**) 11-28-2008

I need to loop through the files in a directory and process the files. But some of the filenames contain spaces.

Here is a little test script I've been using to experiment. (I'm not really going to call 'echo', I'm doing some other processing.) Everything I try fails. How can I do this??

Code:

#!/bin/sh
# spacetest
DIR="/tmp/spacetest$$"
rm -rf $DIR
mkdir -p $DIR || exit 1
touch $DIR/{"a b","c d"}

# This works, when I itemize filenames a priori
set "a b" "c d"
for x in "$@"; do
    echo $x
done

echo Test 1:    # Fails
for x in $(find $DIR -mindepth 1 -printf '"%f" '); do
    echo $x
done

echo Test 2:    # Fails
set $(find $DIR -mindepth 1 -printf '%f ')
for x in "$@"; do
    echo $x
done

echo Test 3:    # Fails
set $(find $DIR -mindepth 1 -printf '"%f" ')
for x in "$@"; do
    echo $x
done

echo Test 4:    # Fails
_list="$(find $DIR -mindepth 1 -printf '"%f" ')"
set $_list
for x in "$@"; do
    echo $x
done

rm -rf $DIR

cfajohnson · #2 (**permalink**) 11-28-2008

Quote:

Originally Posted by KenJackson

I need to loop through the files in a directory and process the files. But some of the filenames contain spaces.
...

Code:

#!/bin/sh
# spacetest
DIR="/tmp/spacetest$$"
####
echo Test 1:    # Fails
for x in $(find $DIR -mindepth 1 -printf '"%f" '); do
    echo $x
done

Assuming there are no newlines in any filenames:
Code:
find $DIR -mindepth 1 -printf '"%f" ' |
while IFS= read -r file
do
  echo "$x"
done

joeyg · #3 (**permalink**) 11-28-2008

use of quotes and use of IFS

Code:

> cat see_blanks
ls -l file* 
ls | grep "file" >f_list

while read filename
  do
  echo "### echo"
  echo $filename
  echo "### ls"
  ls $filename
  echo "### ls in quotes"
  ls "$filename"
  echo "### play with IFS"
  OLDIFS=$IFS
  IFS="~"
  ls $filename
  IFS=$OLDIFS

done<f_list

prorgam execution

Code:

> see_blanks
-rw-rw---- 1 xxx dp 0 Nov 28 10:04 file 04
-rw-rw---- 1 xxx dp 0 Nov 28 10:04 file01
### echo
file 04
### ls
ls: cannot access file: No such file or directory
ls: cannot access 04: No such file or directory
### ls in quotes
file 04
### play with IFS
file 04
### echo
file01
### ls
file01
### ls in quotes
file01
### play with IFS
file01

So, if I use the variable inside quotes, it works. And if I reset the IFS setting then I do not break-apart the commands at each space.

KenJackson · #4 (**permalink**) 01-07-2009

I made some progress with input from this forum, thank you, but I'm down to one stick point. Consider this simpler script:

Code:

#!/bin/sh
VAR=
echo 'A A
B B
C C' | while read f; do
    VAR="$VAR:$f"
    echo $f
done
echo "VAR=${VAR}"

The output is

Code:

A A
B B
C C
VAR=

The f variable echos properly in the loop, but I just can't seem to assign it's value to any other variable.
Why not?

cfajohnson · #5 (**permalink**) 01-07-2009

Quote:

Originally Posted by KenJackson

I made some progress with input from this forum, thank you, but I'm down to one stick point. Consider this simpler script:

Code:

#!/bin/sh
VAR=
echo 'A A
B B
C C' | while read f; do
    VAR="$VAR:$f"
    echo $f
done
echo "VAR=${VAR}"

The output is

Code:

A A
B B
C C
VAR=

The f variable echos properly in the loop, but I just can't seem to assign it's value to any other variable.
Why not?

Each element of a pipeline is executed in its own subshell and therefore cannot affect the parent shell.

Try echo "$VAR" inside the loop, and you'll see that it does get assigned to.

KenJackson · #6 (**permalink**) 01-08-2009

Quote:

Originally Posted by cfajohnson

Each element of a pipeline is executed in its own subshell and therefore cannot affect the parent shell.

Oh. How terribly inconvenient.

Oh, well. I may have stumbled upon a different solution:

Code:

$!/bin/sh
VAR="$(ls | tr '\n' :)"
echo "VAR=$VAR"

If I have files "A A", "B B" and "C C", I'll get this result:

Code:

VAR=A A:B B:C C:

Now I can work with VAR like this:

Code:

#!/bin/sh
while [ -n "$VAR" ]; do
    f="${VAR%%:*}"
    VAR="${VAR#*:}"
    # process "$f" ...
done

cfajohnson · #7 (**permalink**) 01-08-2009

Quote:

Originally Posted by KenJackson

Oh. How terribly inconvenient.

Oh, well. I may have stumbled upon a different solution:

Code:

$!/bin/sh
VAR="$(ls | tr '\n' :)"
echo "VAR=$VAR"

You don't need any external commands to do that:
Code:
VAR=$( printf "%s:" * )
In bash, 3.1 and later, you can do it with:
Code:
printf -v VAR "%s:" *

Quote:

If I have files "A A", "B B" and "C C", I'll get this result:

Code:

VAR=A A:B B:C C:

Now I can work with VAR like this:

Code:

#!/bin/sh
while [ -n "$VAR" ]; do
    f="${VAR%%:*}"
    VAR="${VAR#*:}"
    # process "$f" ...
done

What's wrong with:
Code:
for f in *
do
    : # process "$f" ...
done

More UNIX and Linux Forum Topics You Might Find Helpful
Thread	Thread Starter	Forum	Replies	Last Post
spaces in filenames	Bab00shka	Shell Programming and Scripting	8	09-30-2008 03:13 PM
looping thru filenames in a directory	silas.john	Shell Programming and Scripting	1	07-02-2008 09:27 AM
spaces in filenames, for do	naviztirf	Shell Programming and Scripting	4	10-17-2007 06:08 PM
how to handle spaces in filenames	rayne	Shell Programming and Scripting	4	11-19-2006 01:37 PM
spaces in filenames	Hitori	Shell Programming and Scripting	4	07-04-2006 05:35 PM

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Switch to Linear Mode Hybrid Mode Switch to Threaded Mode	Rate This Thread: