Add eBPF tracing tools and w3m terminal browser

Add bpftrace, bcc-tools, and perf for system tracing and profiling.
These are Linux's eBPF-based equivalents to DTrace, essential for
debugging and performance analysis in rescue scenarios.

Add w3m terminal browser alongside existing lynx for better rendering
of complex pages.

Update RESCUE-GUIDE.txt with new sections covering:
- Section 9: System Tracing with bpftrace examples, BCC tools, perf
- Section 10: Terminal web browsing with lynx/w3m basics

1 files changed, 158 insertions, 0 deletions

diff --git a/custom/RESCUE-GUIDE.txt b/custom/RESCUE-GUIDE.txt
index 70a4120..53760c8 100644
--- a/custom/RESCUE-GUIDE.txt
+++ b/custom/RESCUE-GUIDE.txt
@@ -14,6 +14,8 @@ Table of Contents:
   6. Disk Operations
   7. Network Troubleshooting
   8. Encryption & GPG
+  9. System Tracing (eBPF/bpftrace)
+  10. Terminal Web Browsing
 
 ================================================================================
 1. ZFS RECOVERY
@@ -2436,5 +2438,161 @@ ENCRYPTION TIPS
 9. pass stores passwords as GPG-encrypted files - need your GPG key to access
 
 ================================================================================
+9. SYSTEM TRACING (eBPF/bpftrace)
+================================================================================
+
+Linux equivalent of DTrace. Uses eBPF (extended Berkeley Packet Filter) for
+safe, dynamic kernel tracing. Essential for diagnosing performance issues,
+kernel problems, and understanding system behavior.
+
+QUICK REFERENCE
+---------------
+  tldr bpftrace        # Quick examples
+  man bpftrace         # Full manual
+  bpftrace -l          # List available probes
+  bpftrace -e 'BEGIN { printf("hello\n"); }'  # Test it works
+
+TOOLS AVAILABLE
+---------------
+  bpftrace    - High-level tracing language (like DTrace)
+  bcc-tools   - 100+ pre-built diagnostic tools
+  perf        - Linux kernel profiler
+
+USEFUL BCC TOOLS (run as root)
+------------------------------
+  execsnoop        # Trace new process execution
+  opensnoop        # Trace file opens
+  biolatency       # Block I/O latency histogram
+  tcpconnect       # Trace TCP connections
+  tcpaccept        # Trace TCP accepts
+  ext4slower       # Trace slow ext4 operations
+  zfsslower        # Trace slow ZFS operations (if available)
+  runqlat          # CPU scheduler latency
+  cpudist          # CPU usage distribution
+  cachestat        # Page cache hit/miss stats
+  memleak          # Memory leak detector
+
+BPFTRACE ONE-LINERS
+-------------------
+Count system calls by process:
+
+  bpftrace -e 'tracepoint:raw_syscalls:sys_enter { @[comm] = count(); }'
+
+Trace disk I/O latency histogram:
+
+  bpftrace -e 'kprobe:blk_account_io_start { @start[arg0] = nsecs; }
+               kprobe:blk_account_io_done /@start[arg0]/
+               { @usecs = hist((nsecs - @start[arg0]) / 1000); delete(@start[arg0]); }'
+
+Trace file opens:
+
+  bpftrace -e 'tracepoint:syscalls:sys_enter_open { printf("%s %s\n", comm, str(args->filename)); }'
+
+Trace TCP connections:
+
+  bpftrace -e 'kprobe:tcp_connect { printf("%s connecting\n", comm); }'
+
+Profile kernel stacks at 99Hz:
+
+  bpftrace -e 'profile:hz:99 { @[kstack] = count(); }'
+
+ZFS-SPECIFIC TRACING
+--------------------
+Trace ZFS reads:
+
+  bpftrace -e 'kprobe:zfs_read { @[comm] = count(); }'
+
+Trace ZFS writes:
+
+  bpftrace -e 'kprobe:zfs_write { @[comm] = count(); }'
+
+PERF BASICS
+-----------
+Record CPU profile for 10 seconds:
+
+  perf record -g sleep 10
+
+View the report:
+
+  perf report
+
+List available events:
+
+  perf list
+
+Real-time top-like view:
+
+  perf top
+
+LEARN MORE
+----------
+  https://www.brendangregg.com/bpf-performance-tools-book.html
+  https://github.com/iovisor/bcc
+  https://github.com/iovisor/bpftrace
+  https://www.brendangregg.com/ebpf.html
+
+
+================================================================================
+10. TERMINAL WEB BROWSING
+================================================================================
+
+Two terminal web browsers available for documentation and troubleshooting.
+
+BROWSERS AVAILABLE
+------------------
+  lynx    - Classic text browser, most compatible, keyboard-driven
+  w3m     - Better table rendering, can display images in some terminals
+
+LYNX BASICS
+-----------
+Start browsing:
+
+  lynx https://wiki.archlinux.org
+  lynx file.html
+
+Navigation:
+  Arrow keys  - Move around
+  Enter       - Follow link
+  Backspace   - Go back
+  q           - Quit
+  /           - Search in page
+  g           - Go to URL
+  p           - Print/save page
+
+W3M BASICS
+----------
+Start browsing:
+
+  w3m https://wiki.archlinux.org
+  w3m file.html
+
+Navigation:
+  Arrow keys  - Scroll
+  Enter       - Follow link
+  B           - Go back
+  U           - Enter URL
+  q           - Quit (Q to quit without confirm)
+  /           - Search forward
+  Tab         - Next link
+  Shift+Tab   - Previous link
+
+USEFUL URLS FOR RESCUE
+----------------------
+  https://wiki.archlinux.org
+  https://wiki.archlinux.org/title/ZFS
+  https://wiki.archlinux.org/title/GRUB
+  https://wiki.archlinux.org/title/Mkinitcpio
+  https://bbs.archlinux.org
+  https://openzfs.github.io/openzfs-docs/
+
+SAVE PAGE FOR OFFLINE
+---------------------
+  lynx -dump URL > page.txt           # Save as text
+  w3m -dump URL > page.txt            # Save as text
+  wget -p -k URL                      # Download with assets
+  curl URL > page.html                # Just the HTML
+
+
+================================================================================
                               END OF GUIDE
 ================================================================================