shell script interpolation of variables containing spaces [was: afio batch operation]
On 11/6/22 05:01, Greg Wooledge wrote:
> On Sun, Nov 06, 2022 at 08:50:16PM +0800, jeremy ardley wrote:
>> On 6/11/22 19:38, Thomas Schmitt wrote:
>>> Then unpack the archive files:
>>>
>>> for i in "$archive_dir"/*.afio.bz2
>>> do
>>> # One of:
>>> # afio -ivZ -P bzip2
>> Corrected:
>>
>> afio -ivZ -P bzip2 $i
>>
>>> # bunzip2 < "$i" | afio -iv -
>>> done
>
> The "$i" needs to be "double-quoted", or else it will fail on files
> that have whitespace or globbing characters in their names.
+1
See below for a /bin/sh script that demonstrates shell interpolation of
a variable containing spaces with no quotes, with double quotes, with
single quotes, with nested double single quotes, and with nested single
double quotes.
Shell interpolation of a variable containing shell globbing characters
is left as an exercise for the reader (virtual machine clone advised).
David
2022-11-06 10:16:42 dpchrist@laalaa
~/sandbox/sh/debian-user/20221106-0501-greg-wooledge
$ cat /etc/debian_version ; uname -a
11.5
Linux laalaa 5.10.0-19-amd64 #1 SMP Debian 5.10.149-2 (2022-10-21)
x86_64 GNU/Linux
2022-11-06 10:31:21 dpchrist@laalaa
~/sandbox/sh/debian-user/20221106-0501-greg-wooledge
$ cat script.sh
#!/bin/sh
# $Id: script.sh,v 1.6 2022/11/06 18:31:10 dpchrist Exp $
f='filename with spaces'
rm -f $f "$f" '$f' "'$f'" '"$f"'
echo "no quotes"
touch $f
ls -ldQ *
rm -f $f "$f" '$f' "'$f'" '"$f"'
echo "double quotes"
touch "$f"
ls -ldQ *
rm -f $f "$f" '$f' "'$f'" '"$f"'
echo "single quotes"
touch '$f'
ls -ldQ *
rm -f $f "$f" '$f' "'$f'" '"$f"'
echo "nested double single quotes"
touch "'$f'"
ls -ldQ *
rm -f $f "$f" '$f' "'$f'" '"$f"'
echo "nested single double quotes"
touch '"$f"'
ls -ldQ *
rm -f $f "$f" '$f' "'$f'" '"$f"'
2022-11-06 10:31:23 dpchrist@laalaa
~/sandbox/sh/debian-user/20221106-0501-greg-wooledge
$ /bin/sh script.sh
no quotes
drwxr-xr-x 2 dpchrist dpchrist 4096 Nov 6 10:31 "CVS"
-rw-r--r-- 1 dpchrist dpchrist 0 Nov 6 10:31 "filename"
-rwxr-xr-x 1 dpchrist dpchrist 539 Nov 6 10:31 "script.sh"
-rw-r--r-- 1 dpchrist dpchrist 0 Nov 6 10:31 "spaces"
-rw-r--r-- 1 dpchrist dpchrist 0 Nov 6 10:31 "with"
double quotes
drwxr-xr-x 2 dpchrist dpchrist 4096 Nov 6 10:31 "CVS"
-rw-r--r-- 1 dpchrist dpchrist 0 Nov 6 10:31 "filename with spaces"
-rwxr-xr-x 1 dpchrist dpchrist 539 Nov 6 10:31 "script.sh"
single quotes
-rw-r--r-- 1 dpchrist dpchrist 0 Nov 6 10:31 "$f"
drwxr-xr-x 2 dpchrist dpchrist 4096 Nov 6 10:31 "CVS"
-rwxr-xr-x 1 dpchrist dpchrist 539 Nov 6 10:31 "script.sh"
nested double single quotes
-rw-r--r-- 1 dpchrist dpchrist 0 Nov 6 10:31 "'filename with spaces'"
drwxr-xr-x 2 dpchrist dpchrist 4096 Nov 6 10:31 "CVS"
-rwxr-xr-x 1 dpchrist dpchrist 539 Nov 6 10:31 "script.sh"
nested single double quotes
-rw-r--r-- 1 dpchrist dpchrist 0 Nov 6 10:31 "\"$f\""
drwxr-xr-x 2 dpchrist dpchrist 4096 Nov 6 10:31 "CVS"
-rwxr-xr-x 1 dpchrist dpchrist 539 Nov 6 10:31 "script.sh"
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