unix permissions converter in symbolic notation (including sticky bit)

The sed command takes multiple -e 'sed-command' options, so it is trivial to fix your code so that it uses one invocation of sed:

stat --format '%A' a |sed -E -e 's/^.(...)(...)(...)/u=\1,g=\2,o=\3/g' \       -e 's/s/xs/g' \       -e 's/t/xt/g' \           -e 's/S/s/g' \       -e 's/T/t/g' \       -e 's/-//g' \       -e 's/=(,|$)/-rwx\1/g'

You can't use the trailing comments, but this is otherwise the same as what you showed. Your s/s/xs/g operation doesn't match what you describe as the output you want (you show sx and not xs for the SGID with group execute permissions). There are those who'd smush all those options into a single -e option with semicolons separating the expressions. I prefer to use -e to separate separate options. There are times when the -f script.sed option to read the script from a file is sensible. I don't think this script has reached that threshold yet, but don't forget that the option exists.

Beauty is in the eye of the beholder. I'm not convinced that the alternative representation for permissions is very much better than the normal one, but maybe I've just been using Unix too long.

Finally the more concise command I have found is :

stat --format '%A' myFile | sed -E -e 's/(...)(...)(...)$/u=\1,g=\2,o=\3/;s/(s|t)/x\1/g;s/(S|T)/\l\1/g;s/-//g;s/(u|g)=,/\1-rwxs,/g;s/o=$/o-rwxt/g'

I would have preferred to find a native command

To be sure I have written an exhaustive bash to test all combination of rights (8*8*8*8 = 4096 cases !)

test_file=/tmp/areturn_code=0echo -e "from itertools import product;\nfor mod in  product('01234567', repeat=4) : print ''.join(mod)" | python | shuf |while read octalModdo  chmod $octalMod $test_file  # apply octal mod  # get symbolic mod  symbolicMod=$(stat --format '%A' $test_file | sed -E -e 's/(...)(...)(...)$/u=\1,g=\2,o=\3/;s/(s|t)/x\1/g;s/(S|T)/\l\1/g;s/-//g;s/(u|g)=,/\1-rwxs,/g;s/o=$/o-rwxt/g')  chmod 0000 $test_file          # reset mod  chmod $symbolicMod $test_file  # apply symbolic mod  modActual=$(stat --format '%a' $test_file) # get actual mod in octal format to compare it with the original  if [ $octalMod -ne $modActual ]  then    echo "$octalMod ($symbolicMod) !!! octalMod=$octalMod <> modActual=$modActual" >&2    return_code=255  else    echo "$octalMod ($symbolicMod)     octalMod=$octalMod == modActual=$modActual" >&1  fidoneexit $return_code

Complete list :

test_file=/tmp/aecho -e "octalMod\thumanMod\tsymbolicMod"echo -e "from itertools import product;\nfor mod in  product('01234567', repeat=4) : print ''.join(mod)" | python |while read octalModdo  chmod $octalMod $test_file  # apply octal mod  # get symbolic mod  symbolicMod=$(stat --format '%A' $test_file | sed -E -e 's/(...)(...)(...)$/u=\1,g=\2,o=\3/;s/(s|t)/x\1/g;s/(S|T)/\l\1/g;s/-//g;s/(u|g)=,/\1-rwxs,/g;s/o=$/o-rwxt/g')  humanMod=$(stat --format '%A' $test_file)  echo -e "$octalMod\t$humanMod\t$symbolicMod"doneecho -e "octalMod\thumanMod\tsymbolicMod"

sample result :

octalMod        humanMod        symbolicMod0001    ---------x      u-rwxs,g-rwxs,o=x0354    --wxr-xr--      u=wx,g=rx,o=r1210    --w---x--T      u=w,g=x,o=t3337    --wx-wsrwt      u=wx,g=wxs,o=rwxt3566    -r-xrwSrwT      u=rx,g=rws,o=rwt3734    -rwx-wsr-T      u=rwx,g=wxs,o=rt6734    -rws-wsr--      u=rwxs,g=wxs,o=r7121    ---s-wS--t      u=xs,g=ws,o=xt7430    -r-S-ws--T      u=rs,g=wxs,o=t7611    -rwS--s--t      u=rws,g=xs,o=xt