add bash scripts

code/misc/bash/nnn/preview_cmd.sh

@@ -0,0 +1,46 @@
+#!/usr/bin/env sh
+# #############################################################################
+# File: preview_cmd.sh
+# Description: Minimal example to preview files and directories
+#              No external dependencies
+#              Can be easily extended
+#              Automatically exits when the NNN_FIFO closes
+#              Prints a `tree` if directory or `head` if it's a file
+#
+# Shell: POSIX compliant
+# Author: Todd Yamakawa
+#
+# ToDo:
+#   1. Add support for more types of files
+#         e.g. binary files, we shouldn't try to `head` those
+# #############################################################################
+
+# Check FIFO
+NNN_FIFO=${NNN_FIFO:-$1}
+if [ ! -r "$NNN_FIFO" ]; then
+    echo "Unable to open \$NNN_FIFO='$NNN_FIFO'" | less
+    exit 2
+fi
+
+# Read selection from $NNN_FIFO
+while read -r selection; do
+    clear
+    lines=$(($(tput lines)-1))
+    cols=$(tput cols)
+
+    # Print directory tree
+    if [ -d "$selection" ]; then
+        cd "$selection" || continue
+        tree | head -n $lines | cut -c 1-"$cols"
+        continue
+    fi
+
+    # Print file head
+    if [ -f "$selection" ]; then
+        head -n $lines "$selection" | cut -c 1-"$cols"
+        continue
+    fi
+
+    # Something went wrong
+    echo "Unknown type: '$selection'"
+done < "$NNN_FIFO"