Test script that shows what file descriptors a shell opens.

oilshell · Jan 11, 2018 · e956abea08e29629142d97dd2c0b908cb234b232 · e956abe
1 parent 98d3965
commit e956abea08e29629142d97dd2c0b908cb234b232
Unified Split

Showing with 31 additions and 0 deletions.

+31 −0 gold/open-fds.sh
diff --git a/gold/open-fds.sh b/gold/open-fds.sh
@@ -0,0 +1,31 @@
+#!/bin/sh
+
+# bash: descriptors 10 and 255
+# osh: 3 and 4 taken: BAD
+
+# dash: 10 and 11
+# mksh: 24 25 26
+# zsh: 10 11 12.  zsh somehow doesn't run this script correctly.  It's not
+# POSIX I guess.
+
+# count FDs greater than 10.  0-9 are reserved for scripts.
+count_fds() {
+  local count=0
+  local reserved=0
+  {
+    for path in /proc/$$/fd/*; do
+      echo $path
+      count=$((count + 1))
+      if test $(basename $path) -lt 10; then
+        reserved=$((reserved + 1))
+      fi
+    done
+
+    echo "$count FDs open; $reserved are RESERVED (0-9)"
+
+  } 2> _tmp/err.txt
+
+}
+
+"$@"
+