Display monitor info via command line

Yes there is, read-edid hardware information-gathering tool for VESA PnP monitors. This tool have two commands: get-edid and parse-edid: tools to retrieve and interpret monitor specifications using the VESA VBE DDC protocol. EDID (Extended Display Identification Data) is a metadata format for display devices to describe their capabilities to a video source.

First:

sudo apt-get install read-edid

Then try:

sudo get-edid | parse-edid

$ grep "NVIDIA(GPU-0)" /var/log/Xorg.0.log |head -17| cut -d\: -f2
 Display (Samsung SA300/SA350 (DFP-0)) does not support NVIDIA
     3D Vision stereo.
 The EDID for Samsung SA300/SA350 (DFP-0) contradicts itself
     mode "1920x1080" is specified in the EDID; however, the
     EDID's valid VertRefresh range (56.000-75.000 Hz) would
     exclude this mode's VertRefresh (50.0 Hz); ignoring
     VertRefresh check for mode "1920x1080".
 The EDID for Samsung SA300/SA350 (DFP-0) contradicts itself
     mode "1280x720" is specified in the EDID; however, the
     EDID's valid VertRefresh range (56.000-75.000 Hz) would
     exclude this mode's VertRefresh (50.0 Hz); ignoring
     VertRefresh check for mode "1280x720".
 The EDID for Samsung SA300/SA350 (DFP-0) contradicts itself
     mode "720x576" is specified in the EDID; however, the
     EDID's valid VertRefresh range (56.000-75.000 Hz) would
     exclude this mode's VertRefresh (50.0 Hz); ignoring
     VertRefresh check for mode "720x576".

Case where get-edid does not show all monitors

Like mine, I have:

$ lshw -c display
  *-display               
       description: VGA compatible controller
       product: 3rd Gen Core processor Graphics Controller
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 09
       width: 64 bits
       clock: 33MHz
       capabilities: vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:27 memory:f6400000-f67fffff memory:e0000000-efffffff ioport:f000(size=64)

get-edid shows only the external monitor which is plugged to VGA port.

1. Install read-edid

    sudo apt-get install read-edid
   

2. Read EDID info directly from SYSFS tree, it should show all detected monitors

    ls /sys/class/drm/*/edid | xargs -i{} sh -c "echo {}; parse-edid < {}"
   

Try

xrandr

(I used the program once when I was playing with dual monitor setup on Archlinux .)

You can find it in the x11-server-utils package. That package contains other stuff to play with like:

• iceauth, a tool for manipulating ICE protocol authorization records;
• rgb;
• sessreg, a simple program for managing utmp/wtmp entries;
• xcmsdb, a device color characteristic utility for the X Color Management System;
• xgamma, a tool for querying and setting a monitor's gamma correction;
• xhost, a very dangerous program that you should never use;
• xmodmap, a utility for modifying keymaps and pointer button mappings in X;
• xrandr, a command-line interface to the RandR extension;
• xrdb, a tool to manage the X server resource database;
• xrefresh, a tool that forces a redraw of the X screen;
• xset, a tool for setting miscellaneous X server parameters;
• xsetmode and xsetpointer, tools for handling X Input devices;
• xsetroot, a tool for tailoring the appearance of the root window;
• xstdcmap, a utility to selectively define standard colormap properties;
• xvidtune, a tool for customizing X server modelines for your monitor. (information found in synaptic package manager)