Create array: array=($(ls -l))
Show full an array: echo ${array[#]}
Result: total 0 -rw-r--r-- 1 root root 0 Jul 14 05:54 1 -rw-r--r-- 1 root root 0 Jul 14 05:54 2 -rw-r--r-- 1 root root 0 Jul 14 05:54 3 -rw-r--r-- 1 root root 0 Jul 14 05:54 4 -rw-r--r-- 1 root root 0 Jul 14 05:54 5
Show part of an array: echo ${array[#]:0:11}
Result: total 0 -rw-r--r-- 1 root root 0 Jul 14 05:54 1
Show other part of an array: echo ${array[#]:11:20}
Result: -rw-r--r-- 1 root root 0 Jul 14 05:54 2 -rw-r--r-- 1 root root 0 Jul 14 05:54 3 -rw-r--r-- 1
Why not only elements 11-20 are shown, but also the rest?
I have 11 i2c device nodes on my system.
localhost user # ls /dev/i2c*
/dev/i2c-0 /dev/i2c-1 /dev/i2c-10 /dev/i2c-2 /dev/i2c-3 /dev/i2c-4 /dev/i2c-5 /dev/i2c-6 /dev/i2c-7 /dev/i2c-8 /dev/i2c-9
I can figure out which one is which by poking around in the /sys filesystem:
localhost devices # pwd
/sys/bus/i2c/devices
localhost devices # ls -al
total 0
drwxr-xr-x 2 root root 0 Jan 10 15:45 .
drwxr-xr-x 4 root root 0 Jan 10 15:45 ..
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-0 -> ../../../devices/pci0000:00/0000:00:02.0/i2c-0
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-1 -> ../../../devices/pci0000:00/0000:00:02.0/i2c-1
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-10 -> ../../../devices/pci0000:00/0000:00:19.2/i2c_designware.5/i2c-10
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-10508825:00 -> ../../../devices/pci0000:00/0000:00:19.2/i2c_designware.5/i2c-10/i2c-10508825:00
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-2 -> ../../../devices/pci0000:00/0000:00:02.0/i2c-2
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-3 -> ../../../devices/pci0000:00/0000:00:02.0/i2c-3
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-4 -> ../../../devices/pci0000:00/0000:00:02.0/i2c-4
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-5 -> ../../../devices/pci0000:00/0000:00:02.0/i2c-5
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-6 -> ../../../devices/pci0000:00/0000:00:15.0/i2c_designware.0/i2c-6
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-7 -> ../../../devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-7
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-8 -> ../../../devices/pci0000:00/0000:00:15.2/i2c_designware.2/i2c-8
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-9 -> ../../../devices/pci0000:00/0000:00:15.3/i2c_designware.3/i2c-9
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-INT343B:00 -> ../../../devices/pci0000:00/0000:00:19.2/i2c_designware.5/i2c-10/i2c-INT343B:00
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-INT343B:01 -> ../../../devices/pci0000:00/0000:00:19.2/i2c_designware.5/i2c-10/i2c-INT343B:01
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-PRP0001:00 -> ../../../devices/pci0000:00/0000:00:15.2/i2c_designware.2/i2c-8/i2c-PRP0001:00
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-PRP0001:01 -> ../../../devices/pci0000:00/0000:00:15.3/i2c_designware.3/i2c-9/i2c-PRP0001:01
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-SYNA7817:00 -> ../../../devices/pci0000:00/0000:00:15.0/i2c_designware.0/i2c-6/i2c-SYNA7817:00
lrwxrwxrwx 1 root root 0 Jan 10 15:45 i2c-SYNA7817:01 -> ../../../devices/pci0000:00/0000:00:15.1/i2c_designware.1/i2c-7/i2c-SYNA7817:01
The ones that I want are i2c-PRP0001-*, which I can see are currently symlinked to i2c-8 and i2c-9.
i2c offers no guarantee that these node numbers are stable (even across reboots). I would like to give my program the ability to look at an i2c device and determine if it's one I care about or not.
I could hack up a shell script to do basically what I just did on the command line, but is there a programmatic (C) way to find the device information (i.e. where does the kernel get the information that it writes to the sys filesystem)?
I hope build ruby c extension with cmake, but I get /usr/bin/ld: cannot find -llibruby in console, here is my code:
CMakeLists.txt
cmake_minimum_required(VERSION 3.3)
set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -std=c11")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11")
file(GLOB cs *.c)
include_directories($ENV{HOME}/.rbenv/versions/2.2.3/include/ruby-2.2.0/x86_64-linux
$ENV{HOME}/.rbenv/versions/2.2.3/include/ruby-2.2.0)
foreach (c ${cs})
get_filename_component(exe ${c} NAME_WE)
add_executable(${exe} ${cs})
endforeach ()
add_library(mytest SHARED MyTest.c)
link_directories($ENV{HOME}/.rbenv/versions/2.2.3/lib)
find_library(ruby NAMES ruby)
target_link_libraries(mytest ruby)
and here is ruby lib:
roroco#roroco-Zhaoyang-K49 ~/Dropbox/rbs/ro_plans $ lsa ~/.rbenv/versions/2.2.3/lib
total 61424
drwxr-xr-x 4 roroco roroco 4096 Nov 21 23:49 .
drwxr-xr-x 6 roroco roroco 4096 Oct 13 22:10 ..
lrwxrwxrwx 1 roroco roroco 16 Nov 21 23:49 libruby.so -> libruby.so.2.2.0
lrwxrwxrwx 1 roroco roroco 16 Nov 21 23:49 libruby.so.2.2 -> libruby.so.2.2.0
-rwxr-xr-x 1 roroco roroco 13573794 Nov 21 23:49 libruby.so.2.2.0
-rw-r--r-- 1 roroco roroco 49306632 Nov 21 23:47 libruby-static.a
drwxr-xr-x 2 roroco roroco 4096 Nov 21 23:49 pkgconfig
drwxr-xr-x 6 roroco roroco 4096 Oct 13 22:10 ruby
When you do ls -la it returns each path along with info of whether or not it's a file/directory:
$ ls -la
drwxr-xr-x 11 viatropos staff 374 Jan 21 21:24 .
drwxr-xr-x 41 viatropos staff 1394 Feb 2 00:48 ..
-rw-r--r-- 1 viatropos staff 43 Jan 21 21:23 .gitignore
-rw-r--r-- 1 viatropos staff 43 Jan 21 21:23 .npmignore
-rw-r--r-- 1 viatropos staff 647 Jan 21 21:23 README.md
-rw-r--r-- 1 viatropos staff 3069 Feb 5 20:17 index.js
drwxr-xr-x 8 viatropos staff 272 Feb 5 20:06 node_modules
-rw-r--r-- 1 viatropos staff 291 Jan 21 21:24 package.json
drwxr-xr-x 4 viatropos staff 136 Jan 21 21:23 test
Is there a way to do this using the find command (and glob * functionality)? So, finding all paths within node_modules and having it return the path and whether or not it's a file directory? Something like:
$ find node_modules -name 'lib/*'
d node_modules/express/lib/
f node_modules/express/lib/index.js
...
How about find ... -printf '%y %p\n'? (This is probably a GNU find extension, though.)
Try this script, I called it "findfl". The "mtime" clause finds files changed in the last 3 days.
Directories will have "/" appended.
#!/bin/sh
# find files produced recently, matching input pattern
[ $1 ] || { echo "Usage: findfl <file-name-pattern>" ; exit ; }
TOPDIR=/home/usr/fred #the directory you want to search
echo "Searching $TOPDIR"
find . -mtime -3 -name *$1* 2>/dev/null | xargs -n 99 ls -lptr | sed "s! ./! $TOPDIR/!g"
I need to know how I can figure out to which entry in /proc/bus/usb/devices a /dev/sdX device maps to. Basically, I need to know the vendor id and product id of a given USB stick (which may not have a serial number).
In my case, I have this entry for my flash drive in /proc/bus/usb/devices:
T: Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 6 Spd=480 MxCh= 0
D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=0781 ProdID=5530 Rev= 2.00
S: Manufacturer=SanDisk
S: Product=Cruzer
S: SerialNumber=0765400A1BD05BEE
C:* #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=200mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
E: Ad=81(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms
E: Ad=02(O) Atr=02(Bulk) MxPS= 512 Ivl=0ms
I happen to know that in my case it is /dev/sda, but I'm not sure how I can figure this out in code. My first approach was to loop through all /dev/sdXX devices and issue a SCSI_IOCTL_GET_BUS_NUMBER and/or SCSI_IOCTL_GET_IDLUN request, but the information returned doesn't help me match it up:
/tmp # ./getscsiinfo /dev/sda
SCSI bus number: 8
ID: 00
LUN: 00
Channel: 00
Host#: 08
four_in_one: 08000000
host_unique_id: 0
I'm not sure how I can use the SCSI bus number or the ID, LUN, Channel, Host to map it to the entry in /proc/bus/usb/devices. Or how I could get the SCSI bus number from the /proc/bus/usb/001/006 device, which is a usbfs device and doesn't appear to like the same ioctl's:
/tmp # ./getscsiinfo /proc/bus/usb/001/006
Could not get bus number: Inappropriate ioctl for device
Here's the test code for my little getscsiinfo test tool:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <scsi/scsi.h>
#include <scsi/sg.h>
#include <sys/ioctl.h>
struct scsi_idlun
{
int four_in_one;
int host_unique_id;
};
int main(int argc, char** argv) {
if (argc != 2)
return 1;
int fd = open(argv[1], O_RDONLY | O_NONBLOCK);
if (fd < 0)
{
printf("Error opening device: %m\n");
return 1;
}
int busNumber = -1;
if (ioctl(fd, SCSI_IOCTL_GET_BUS_NUMBER, &busNumber) < 0)
{
printf("Could not get bus number: %m\n");
close(fd);
return 1;
}
printf("SCSI bus number: %d\n", busNumber);
struct scsi_idlun argid;
if (ioctl(fd, SCSI_IOCTL_GET_IDLUN, &argid) < 0)
{
printf("Could not get id: %m\n");
close(fd);
return 1;
}
printf("ID: %02x\n", argid.four_in_one & 0xFF);
printf("LUN: %02x\n", (argid.four_in_one >> 8) & 0xFF);
printf("Channel: %02x\n", (argid.four_in_one >> 16) & 0xFF);
printf("Host#: %02x\n", (argid.four_in_one >> 24) & 0xFF);
printf("four_in_one: %08x\n", (unsigned int)argid.four_in_one);
printf("host_unique_id: %d\n", argid.host_unique_id);
close(fd);
return 0;
}
Does anyone have any idea?
udevadm is capable of what your are trying to achieve.
udevadm info -a -p $(udevadm info -q path -n /dev/sda)
udevadm's sources will tell you how it is done.
I believe you can collect such information using libudev library.
Here are some details about it: http://www.signal11.us/oss/udev/
I found something like this on above site:
.. Using libudev, we'll be able to inspect the devices, including their Vendor ID (VID), Product ID (PID), serial number, and device strings, without ever opening the device. Further, libudev will tell us exactly where inside /dev the device's node is located, giving the application a robust and distribution-independent way of accessing the device. ...
This isn't all that easy, nor very well documented (at least from a high-level perspective). The following should work in Kernel's from version 3.1 upward (at least).
I have found the easiest (probably not the only way) is to navigate from the block device entry and test each block device until you find the one that matches your USB entry.
For example, given a block device in /sys/block, such as sdb, you can find the hardware device descriptor entry like this:
# cd /sys/block
# cd $(readlink sdb); cd ../../../../../..
# ls -l
total 0
drwxr-xr-x 6 root root 0 Aug 14 10:47 1-1:1.0
-rw-r--r-- 1 root root 4096 Aug 14 10:52 authorized
-rw-r--r-- 1 root root 4096 Aug 14 10:52 avoid_reset_quirk
-r--r--r-- 1 root root 4096 Aug 14 10:47 bcdDevice
-rw-r--r-- 1 root root 4096 Aug 14 10:49 bConfigurationValue
-r--r--r-- 1 root root 4096 Aug 14 10:47 bDeviceClass
-r--r--r-- 1 root root 4096 Aug 14 10:49 bDeviceProtocol
-r--r--r-- 1 root root 4096 Aug 14 10:49 bDeviceSubClass
-r--r--r-- 1 root root 4096 Aug 14 10:49 bmAttributes
-r--r--r-- 1 root root 4096 Aug 14 10:49 bMaxPacketSize0
-r--r--r-- 1 root root 4096 Aug 14 10:49 bMaxPower
-r--r--r-- 1 root root 4096 Aug 14 10:49 bNumConfigurations
-r--r--r-- 1 root root 4096 Aug 14 10:49 bNumInterfaces
-r--r--r-- 1 root root 4096 Aug 14 10:49 busnum
-r--r--r-- 1 root root 4096 Aug 14 10:52 configuration
-r--r--r-- 1 root root 65553 Aug 14 10:47 descriptors
-r--r--r-- 1 root root 4096 Aug 14 10:52 dev
-r--r--r-- 1 root root 4096 Aug 14 10:49 devnum
-r--r--r-- 1 root root 4096 Aug 14 10:52 devpath
lrwxrwxrwx 1 root root 0 Aug 14 10:47 driver -> ../../../../../../bus/usb/drivers/usb
drwxr-xr-x 3 root root 0 Aug 14 10:52 ep_00
-r--r--r-- 1 root root 4096 Aug 14 10:47 idProduct
-r--r--r-- 1 root root 4096 Aug 14 10:47 idVendor
-r--r--r-- 1 root root 4096 Aug 14 10:52 ltm_capable
-r--r--r-- 1 root root 4096 Aug 14 10:47 manufacturer
-r--r--r-- 1 root root 4096 Aug 14 10:49 maxchild
lrwxrwxrwx 1 root root 0 Aug 14 10:52 port -> ../1-0:1.0/port1
drwxr-xr-x 2 root root 0 Aug 14 10:52 power
-r--r--r-- 1 root root 4096 Aug 14 10:47 product
-r--r--r-- 1 root root 4096 Aug 14 10:52 quirks
-r--r--r-- 1 root root 4096 Aug 14 10:47 removable
--w------- 1 root root 4096 Aug 14 10:52 remove
-r--r--r-- 1 root root 4096 Aug 14 10:47 serial
-r--r--r-- 1 root root 4096 Aug 14 10:49 speed
lrwxrwxrwx 1 root root 0 Aug 14 10:47 subsystem -> ../../../../../../bus/usb
-rw-r--r-- 1 root root 4096 Aug 14 10:47 uevent
-r--r--r-- 1 root root 4096 Aug 14 10:52 urbnum
-r--r--r-- 1 root root 4096 Aug 14 10:49 version
(You can find excellent documentation for the contents of the USB Descriptor here on the BeyondLogic site.)
Given the above, you should be able to map one or more of the USB device fields to the contents of /proc/bus/usb/devices. I find that the serial number is the easiest to match on, so that if you were to cat serial above, you would get the same serial number as listed:
T: Bus=01 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=480 MxCh= 0
D: Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS=64 #Cfgs= 1
P: Vendor=0781 ProdID=5575 Rev=01.26
S: Manufacturer=SanDisk
S: Product=Cruzer Glide
S: SerialNumber=4C530100801115115112
C: #Ifs= 1 Cfg#= 1 Atr=80 MxPwr=200mA
I: If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
If you go to /sys/block, you can list the full path to the host device entry in the storage driver sysfs entry for each device. Typically, I do this using some programmatic means instead of at the shell prompt, but here you can see the links themselves:
# ls -l sd*
lrwxrwxrwx 1 root root 0 Aug 14 10:45 sda -> ../devices/pci0000:00/0000:00:10.0/host32/target32:0:0/32:0:0:0/block/sda
lrwxrwxrwx 1 root root 0 Aug 14 10:47 sdb -> ../devices/pci0000:00/0000:00:11.0/0000:02:03.0/usb1/1-1/1-1:1.0/host33/target33:0:0/33:0:0:0/block/sdb
Note that you mustn't make any assumptions about the numbers you see in the links. Depending upon the bus subsystem, the mappings could be quite different. For example, on a Raspberry Pi, it looks like this:
# ls -l sd*
lrwxrwxrwx 1 root root 0 Aug 13 23:54 sda -> ../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.4/1-1.4:1.0/host3/target3:0:0/3:0:0:0/block/sda
lrwxrwxrwx 1 root root 0 Aug 13 23:54 sdb -> ../devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3/1-1.3:1.0/host4/target4:0:0/4:0:0:0/block/sdb
So, the best approach is to take the approach listed at the top and navigate relative to the storage driver to find the USB device descriptor.
I'd be curious about more authoritative answers to this. The method above was arrived at by trial-and-error but has been working on several different devices and Kernels with no problem.
Instead of using proc/bus/usb which is for usbfs you can use /proc/scsi/scsi. In there you can find the Vendor and Serial number with specific channel ID and LUN number.