A copy-pasteable shell-based interactive line editor, for when I don't have vim in a container and don't want to install it for some reason.

bin-shed

#!/bin/bash
if ! [[ -f "$1" ]] ; then echo "Usage: $0 file-to-edit" ; exit 42 ; fi
FILE=$1
if [[ -f "$FILE~" ]] && ! diff -u $FILE $FILE~ ; then
  echo Resolve or ignore above diffs. Quitting. ; echo rm $FILE~ ; exit 42
fi
cp $FILE $FILE~
help() { echo "Try" ;  grep -E ') *#' $0 ; echo "And ^d to abort" ; }
help
while echo -n ": " ; read ; do
  case "$REPLY" in
    d*) # e.g. d - diff vs original
      diff -u $FILE $FILE~ && echo no diff ;;
    p*|.p*) # e.g. p or p 10 or p 4,6 or p /hello/ - print line/s
      cat -n $FILE~ | sed -n "${REPLY#*p} p" ;;
    s*) # e.g. s 4,6 s/find/replace/ (any sed command like '5d' or '5i insert-before'  or '5a insert-after' with \ for leading space )
      sed -i@ "${REPLY#s}" $FILE~ ;;
    qs*) # Quit and save
      echo "Saving $FILE~ to $FILE" ; mv $FILE~ $FILE ; exit 0 ;;
    qq*) # Quit without saving
      echo "Removing $FILE~ to $FILE~~" ;  mv $FILE~ $FILE~~ ; exit 0 ;;
    *)
      echo "Don't know '$REPLY'" ; help
  esac
done