Shell Programming and Scripting

SriniShoo's code helped !!

However, I need to know how would the same command work if the array contains both files and directories and I wish to check permissions for both.

I tried removing the type -f but that did not help.

Kindly suggest the changes.

---------- Post updated at 11:30 AM ---------- Previous update was at 10:43 AM ----------

660 is lesser than 750 becoz the [6]60 is less than [7]50.
755 is greater than 750 as all the permission are over met.
555 is lesser than 750 becoz [5]55 is less than [7]50.

Please let me know how can i tweak Srini's code to include directories along with files.

Just use "${arr[@]}". You don't need to know how many elements exist nor do you need an external command like seq.


I disagree. Any runtime that can't iterate over its own arrays is badly broken.

Regards,
Alister

Thanks alister for the suggestion! you are correct about using

Code:

${arr[@]}

Below code will search for files / directories with permissions greater than or equal to given

Code:

PERM=750
for i in ${arr[@]}
do
ABS_FILE=$(echo ${i} | awk '{print $9}')
PATH=$(dirname ${ABS_FILE})
FILE=$(basename ${ABS_FILE})
find ${PATH} -name ${FILE} -perm -${PERM}
done

If you give that as the path variable, it will overwrite the default path variable used by the system.

My bad

The problem is not the iteration in itself. The problem is that expanding an array like "${array[*]}" might lead to a line that is longer than "MAXLINE" and/or consisting of more elements than "MAXARGS" allows for. You can experience the same phenomenon when using

Code:

for file in * ; do ...

Thi swill work well for any "normal" directory, but might break with a "line too long" if there are awful lots of entries in there. Instead of the for-loop the while-loop will not break:

Code:

ls | while read file ; do ...

I hope this helps.

bakunin

I'm assuming that by MAXLINE you mean LINE_MAX and that MAXARGS refers to ARG_MAX. In the case of expanding a for-loop's list, neither is relevant.

ARG_MAX limits the size of the command line and environment accepted by the execve system call. The for-loop does not execve the contents of the array; instead, it creates a list and consecutively binds each member to the same identifier.

LINE_MAX is the longest allowable line length (including the terminating newline character) in a text file. Expanding an array into a for-list using "${arr[@]}" does not generate a line or string. That double-quoted parameter expansion, like its positional parameter counterpart, "$@", directly generates a list.

I don't think it's germane, but while we're on the subject of LINE_MAX and sh, POSIX sh exempts shell scripts from this limit:
Historical shells may indeed have hardcoded limits, but I suspect that any shell that supports arrays is sufficiently modern to utilize dynamic memory allocation. Virtual memory is almost certainly the actual limit.

I am not advocating against a while-loop. I have nothing against them. Some of my closest friends are while-loops. My point is simply that categorically advising against a for-loop is a bit much; given a modern shell and sufficient memory, the likelihood of a for-loop meltdown is nil.

There also exists the (remote) possiblity that the for-loop mentioned in the OP is the C-like variant supported by ksh93 and bash, which would allow array traversal using a simple index.

Regards,
Alister