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  • big thank you for this : I used the last (script -qec ....) trick today. I added some commands before and after : ssh host 'cmds before ; SHELL=/bin/sh script -qec "sudo cmdsudoed here with args <&3 >&4 2>&5 3<&- 4>&- 5>&-" /dev/null 3<&0 4>&1 5>&2 ; cmds after here' # the ones after don't display ... probably due to all those &- ? Are they mandatory? (if I understand the order correctly: they retrieve the current values(=fd) of stdin, stdout and stderr, redirects (copy) sudo's in/out/err to the same destinations, then close them for script? thus it closes the outer stdin/out/err too?) Commented Dec 3, 2020 at 13:23
  • moreover I remember reading on this site somewhere that closing fd0 1 or 2 is not recommended: [edit: found it: of course, it was from you :) ) : unix.stackexchange.com/a/446591/27616 : as I don't see output from the commands after the closing of 3, 4, 5: does it mean it closed my ssh shell's 0, 1 and 2 ? and therefore... my successive commands could end up writing in the wrong place? :/ Commented Dec 3, 2020 at 13:35
  • @OlivierDulac, no n>&- (or n<&- which is the same) closes fd n. Only exec 0<&- 1<&- 2<&- (or exec <&- >&- 2>&-) would close stdin/stdout/stderr from now on. We close those fds 3, 4, 5 for sudo, in the shell started by script because neither sudo nor cmd need them and they've served their purpose (restore the original remote shell stdin/out/err inside the script session). I don't know why you don't see the output of cmds after here. Commented Dec 3, 2020 at 14:15
  • Thanks for the answer, I am puzzled as well, and will need further testing to figure why this is happening... Commented Dec 7, 2020 at 8:33
  • Stephane, I have noticed I lose stdout after the first error: in your last (script) exemple, instead of sudo cmd, I have: sudo su - someuser -c \"id ; echo $? ; cd /_not_a_dir_ ; echo $? ; id\" (the rest is the same as in your answer) : I only see the output of the first id and the 0, and then nothing else. I don't see the error from the cd /_not_a_dir_ , nor the subsequent echo $?, nor the last id. if I instead : cd / ; I see all (stdout) outputs Commented Feb 2, 2021 at 16:40