Convert the permissions in `ls -l` output to octal

Question

I want to convert the output of ls to octal permission bits.

I think of the shortest and clearest way to implement that excerise: Let's say that we have as input:

total 1
drwxr----x 1 user2 workers 1024 May 26 22:22 dir
-rwx-wxrw- 2 user2 workers 1024 May 26 22:22 file.txt

our output should be:

741 dir
736 file.txt

Please [Do not parse ls output](http://mywiki.wooledge.org/ParsingLs) — Kiwy, Apr 23 '14 at 00:08
@Kiwy I suspect that this is a homework exercise and the whole point is to parse a string like `drwxr----x`. The serious this-is-how-you-should-do-it-in-practice answers nicely illustrate how trying to disguise homework exercises can backfire. — Gilles 'SO- stop being evil', Apr 23 '14 at 00:47
@StephaneChazelas OK, if I had ever given such an answer I would remember that question, too... — Hauke Laging, Apr 23 '14 at 08:49

score 8 · Answer 1 · edited Apr 23 '14 at 05:33

You could use GNU find:

find . -type f -printf "%m\t%f\n"

In order to obtain the complete path of the file, use the directive p instead of f:

find . -type f -printf "%m\t%p\n"

In order to restrict the results to the current directory, specify -maxdepth:

find . -maxdepth 1 -type f -printf "%m\t%f\n"

If you want results both files and directories, remove the -type predicate:

find . -printf "%m\t%p\n"

score 7 · Answer 2 · edited Apr 23 '14 at 05:34

7

You don't want to use ls for this. On a GNU system, you could use:

stat -c'%a %n' *

edited Apr 23 '14 at 05:34

Stéphane Chazelas

522,931
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1,010
1,501

answered Apr 23 '14 at 00:04

Joseph R.

38,849
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score 2 · Answer 3 · edited Apr 23 '14 at 05:36

2

This may not be the clearest code but from the output quite easy to understand:

echo drwxr----x | 
awk '{chars=substr($1,2); print chars; gsub("-","0",chars); 
gsub("r","4",chars); gsub("w","2",chars); gsub("x","1",chars); 
print chars; for(i=1;i<10;i++) { sum+=substr(chars,i,1); 
if (i%3 == 0) { printf "%d",sum;sum=0; }; } print ""; }'

rwxr----x
421400001
741

(here assuming only the first 9 bits of the permissions are set)

edited Apr 23 '14 at 05:36

Stéphane Chazelas

522,931
91
1,010
1,501

answered Apr 23 '14 at 00:21

Hauke Laging

88,146
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3

@JosephR. The special bits would by a tiny adaption. In any case: Not the answer would be unjustified but the question. And of course we love to do others' homework... – Hauke Laging Apr 23 '14 at 00:28

Convert the permissions in `ls -l` output to octal

3 Answers3