Use python in preference to perl

I know how to make python code robust, no clue about perl.

shell-integration/ssh/bootstrap.sh

@@ -42,13 +42,13 @@ if command -v base64 > /dev/null 2> /dev/null; then
 elif command -v b64encode > /dev/null 2> /dev/null; then
     base64_encode() { command b64encode - | command sed '1d;$d' | command tr -d \\n\\r; }
     base64_decode() { command fold -w 76 | command b64decode -r; }
-elif detect_perl; then
-    base64_encode() { command "$perl" -MMIME::Base64 -0777 -ne 'print encode_base64($_)'; }
-    base64_decode() { command "$perl" -MMIME::Base64 -ne 'print decode_base64($_)'; }
 elif detect_python; then
     pybase64() { command "$python" -c "import sys, base64; getattr(sys.stdout, 'buffer', sys.stdout).write(base64.standard_b64$1(getattr(sys.stdin, 'buffer', sys.stdin).read()))"; }
     base64_encode() { pybase64 "encode"; }
     base64_decode() { pybase64 "decode"; }
+elif detect_perl; then
+    base64_encode() { command "$perl" -MMIME::Base64 -0777 -ne 'print encode_base64($_)'; }
+    base64_decode() { command "$perl" -MMIME::Base64 -ne 'print decode_base64($_)'; }
 else
     die "base64 executable not present on remote host, ssh kitten cannot function."
 fi
@@ -108,19 +108,41 @@ else
         return $?
     }
 
-    if detect_perl; then
+    if [ "$(printf "%s" "test" | command head -c 3 2> /dev/null)" = "tes" ]; then
-        read_n_bytes_from_tty() {
-            command "$perl" -MList::Util=min -e \
-'open(my $fh,"</dev/tty"); binmode($fh); my ($n,$buf)=(@ARGV[0],"");'\
-'while($n){my $rv=sysread($fh,$buf,min(65536,$n)); die($!) if !defined($rv); die() if !$rv; $n-=$rv; print $buf;}' "$1" 2> /dev/null
-        }
-    elif [ "$(printf "%s" "test" | command head -c 3 2> /dev/null)" = "tes" ]; then
         # using dd with bs=1 is very slow, so use head. On non GNU coreutils head
         # does not limit itself to reading -c bytes only from the pipe so we can potentially lose
         # some trailing data, for instance if the user starts typing. Cant be helped.
         read_n_bytes_from_tty() {
             command head -c "$1" < /dev/tty
         }
+    elif detect_python; then
+        read_n_bytes_from_tty() {
+            command "$python" "-c" "
+import sys, os, errno
+def eintr_retry(func, *args):
+    while True:
+        try:
+            return func(*args)
+        except EnvironmentError as e:
+            if e.errno != errno.EINTR:
+                raise
+n = $1
+in_fd = sys.stdin.fileno()
+out_fd = sys.stdout.fileno()
+while n > 0:
+    d = memoryview(eintr_retry(os.read, in_fd, n))
+    n -= len(d)
+    while d:
+        nw = eintr_retry(os.write, out_fd, d)
+        d = d[nw:]
+" < /dev/tty
+        }
+    elif detect_perl; then
+        read_n_bytes_from_tty() {
+            command "$perl" -MList::Util=min -e \
+'open(my $fh,"</dev/tty"); binmode($fh); my ($n,$buf)=(@ARGV[0],"");'\
+'while($n){my $rv=sysread($fh,$buf,min(65536,$n)); die($!) if !defined($rv); die() if !$rv; $n-=$rv; print $buf;}' "$1" 2> /dev/null
+        }
     else
         read_n_bytes_from_tty() {
             command dd bs=1 count="$1" < /dev/tty 2> /dev/null