Interfaces
Audio Devices
When using various Linux Distributions, you may (or may not) run into some issues with audio devices. See some of the configs, logs, and commands below for helpful output in troubleshooting these issues.
GUI Tools / Applications
If looking for a GUI Tool to select or view output / input audio devices, check out pavucontrol -
sudo pacman -Syu pavucontrol
pavucontrol
will install and open the application, which provides a simple interface for selecting audio devices, and even provides application-level audio control, which enables you to easily specify the devices for individual applications instead of forcing a system-wide audio setting for all running apps.
Commands
:)
Sound Card / Devices
Search for all connected audio cards, and output the result.
aplay -L | grep :CARD
List all connected PCI devices (Sound cards are a PCI device)
lspci
Audible Sound Test
The command below will send static to each speaker connected to the device, sequentially, one at a time. Running this will continually test all speakers on a loop, until the user exits with CTRL+C.
speaker-test -D default:PCH -c 8
The output from the above test will look similar to the below, depending on your system and devices.
The -D argument specifies the audio device you want to test. This is useful when not entirely sure which device is valid, you can test quickly with this cmd and make changes later in alsamixer or another config tool with the results of your findings.
The -c argument specifies the number of audio channels you want to test, for my setup I only have a front left and right speaker, so 2 will suffice. If I had a surround sound with Left / Right speakers in the back and an additional center speaker, we would test over 5 channels.
[kapper@kapper-pc ~]$ speaker-test -D default:PCH -c 2
speaker-test 1.1.9
Playback device is default:PCH
Stream parameters are 48000Hz, S16_LE, 2 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 2048 to 16384
Period size range from 1024 to 1024
Using max buffer size 16384
Periods = 4
was set period_size = 1024
was set buffer_size = 16384
0 - Front Left
1 - Front Right
Time per period = 5.648263
0 - Front Left
1 - Front Right
Time per period = 5.973649
0 - Front Left
^CWrite error: -4,Interrupted system call
xrun_recovery failed: -4,Interrupted system call
Transfer failed: Interrupted system call
Sound Mixer / Settings
To open alsa mixer, run the below and use the F6 key to ensure the proper device is selected. This tool can also be used to change volume levels, be careful messing with settings you are unfamiliar with, you could easily blow a speaker. At the least, connect a cheaper pair.
alsamixer
To check device audio settings / levels via CMD -
amixer to list devices and settings
amixer sset Master unmute to mute the Master device. Master can be changed to any valid device name given from the output of amixer
Also, see Advanced Linux Sound Architecture for more information on various documented issues encountered.
Disk Management
Show all disks, usage, and format type
sudo df -T -h
Filesystem Type Size Used Avail Use% Mounted on
udev devtmpfs 930M 4.0K 930M 1% /dev
tmpfs tmpfs 191M 1.5M 190M 1% /run
/dev/sda1 fuseblk 29G 25G 4.5G 85% /isodevice
/dev/loop0 iso9660 1.6G 1.6G 0 100% /cdrom
/dev/loop1 squashfs 1.5G 1.5G 0 100% /rofs
/cow overlay 22G 17G 4.1G 81% /
tmpfs tmpfs 954M 5.2M 949M 1% /dev/shm
tmpfs tmpfs 5.0M 4.0K 5.0M 1% /run/lock
tmpfs tmpfs 954M 0 954M 0% /sys/fs/cgroup
tmpfs tmpfs 954M 56K 954M 1% /tmp
tmpfs tmpfs 191M 8.0K 191M 1% /run/user/999
tmpfs tmpfs 191M 20K 191M 1% /run/user/70000
google-drive-ocamlfuse fuse.google-drive-ocamlfuse 15G 9.1G 6.0G 61% /home/kapper/gdrive
Check /var directories for disk usage, sort and limit results to 10
sudo du -ah /var | sort -nr | head -n 10
924K /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_disco-updates_universe_i18n_Translation-en
924K /var/cache/apparmor/26b63962.0/usr.lib.libreoffice.program.soffice.bin
912K /var/lib/texmf/web2c/pdftex/pdflatex.fmt
912K /var/lib/texmf/web2c/pdftex/latex.fmt
888K /var/cache/apt/archives/libgtkmm-3.0-1v5_3.24.0-2_amd64.deb
852K /var/lib/apt/lists/security.ubuntu.com_ubuntu_dists_disco-security_main_i18n_Translation-en
828K /var/lib/app-info/icons/ubuntu-disco-multiverse
824K /var/lib/dpkg/info/linux-headers-5.0.0-38-generic.md5sums
817K /var/lib/dpkg/info/linux-headers-5.0.0-13-generic.md5sums
804K /var/log/syslog.3.gz
Scan this disk for usage, sort the results by directories > 1.0GB, show largest 5 results
sudo du -xh / | grep '^\S*[0-9\.]\+G' | sort -rn | head -n 5
19G /
9.8G /home/kapper
9.8G /home
6.7G /usr
5.7G /home/kapper/.cache
Show the largest 5 files on the system (greater-than 100MB), using block size of 1MB.
sudo find / -xdev -type f -size +100M -exec ls -l --block-size=M {} \; | sort -nk 5 -r | head -n 5
-rw-r--r-- 1 kapper kapper 174M Nov 30 06:13 /home/kapper/.local/share/JetBrains/Toolbox/apps/CLion/ch-0/213.5744.254/lib/platform-impl.jar
-rw-r--r-- 1 kapper kapper 174M Nov 30 03:14 /home/kapper/.local/share/JetBrains/Toolbox/apps/PyCharm-P/ch-0/213.5744.248/lib/platform-impl.jar
-rw-r--r-- 1 kapper kapper 174M Nov 27 05:41 /home/kapper/.local/share/JetBrains/Toolbox/apps/WebStorm/ch-0/213.5744.224/lib/platform-impl.jar
-rw-r--r-- 1 kapper kapper 174M Nov 23 11:21 /home/kapper/.local/share/JetBrains/Toolbox/apps/datagrip/ch-0/213.5744.178/lib/platform-impl.jar
-rw-r--r-- 1 kapper kapper 174M Dec 1 08:26 /home/kapper/.local/share/JetBrains/Toolbox/apps/Goland/ch-0/213.5744.269/lib/platform-impl.jar
Show the 10 files consuming the most data on this system
sudo find / -printf '%s %p\n'| sort -nr | head -10
140737477885952 /proc/kcore
24244125696 /isodevice/casper-rw
3296907264 /media/lubuntu/37aba99c-8b85-4ddc-92eb-6f50251041e8/encrypted.block
1890263040 /media/lubuntu/37aba99c-8b85-4ddc-92eb-6f50251041e8/home/.shadow/362074638d2508061facd43743c9f08ff66866b8/mount/ASTjdxE5eNzc0F3lkW870B/4HICtmqSNBNCh4oi+U7116prbiG
1657700352 /isodevice/lubuntu-19.04-desktop-amd64.iso
1589342208 /cdrom/casper/filesystem.squashfs
471728128 /media/lubuntu/37aba99c-8b85-4ddc-92eb-6f50251041e8/home/.shadow/362074638d2508061facd43743c9f08ff66866b8/mount/ASTjdxE5eNzc0F3lkW870B/MK3nlrbwT+ZzY8n1fczEqB/Yqt2q,akFt0uJ7WDNJaHdNA0GbkTnhX7kza2zeVnGMI/E1hEyvd6NZ1+JT6hgxI2zA/JekSpYOtLWQPV0kgorVJuFbCcIG/LRriMSOWaunntY7RsNUiUC/x+gYqqpRFtEjXG+JzztvwlQ4LDeq82QY
268435456 /sys/devices/pci0000:00/0000:00:02.0/resource2_wc
268435456 /sys/devices/pci0000:00/0000:00:02.0/resource2
137797651 /home/kapper/.local/share/Steam/ubuntu12_64/libcef.so
Print information on all connected block devices
sudo lsblk
sda 8:0 0 931.5G 0 disk
├─sda1 8:1 0 128M 0 part
├─sda2 8:2 0 925.5G 0 part
└─sda3 8:3 0 5.9G 0 part
Print the UUIDs of all connected block devices, along with some other hardware information
sudo blkid
/dev/sdb2: UUID="436b3ae3-4301-4b8a-80d3-fdf52c7d7059" TYPE="swap" PARTUUID="590670f6-3b89-41b5-b474-fcd6c048628d"
Print information on partitions one all connected block devices
sudo parted -l
Model: HDD A12345678-B3210 (scsi)
Disk /dev/sdb: 2000GB
Sector size (logical/physical): 512B/4096B
Partition Table: gpt
Disk Flags:
Number Start End Size File system Name Flags
1 1049kB 1000MB 999MB fat32 boot, esp
2 1000MB 17.0GB 16.0GB linux-swap(v1)
3 17.0GB 117GB 100GB ext4
4 117GB 217GB 100GB ext4
5 217GB 427GB 210GB ext4
Print information given a specific block device (partitions)
sudo tune2fs -l /dev/sdb3
tune2fs 1.45.4 (23-Sep-2019)
Filesystem volume name: <none>
Last mounted on: /
Filesystem UUID: fagbraetd325t9-6gafdee7-4d2344agdd-93d2-6f4safsafsa5d6
Filesystem magic number: 0xEF53
Filesystem revision #: 1 (dynamic)
Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent 64bit flex_bg sparse_super large_file huge_file dir_nlink extra_isize metadata_csum
Filesystem flags: signed_directory_hash
Default mount options: user_xattr acl
Filesystem state: clean
Errors behavior: Continue
Filesystem OS type: Linux
Filesystem created: Mon Oct 14 12:34:48 2019
Last mount time: Thu Oct 24 12:27:30 2019
Last write time: Thu Oct 24 12:27:30 2019
Mount count: 50
Maximum mount count: -1
Lifetime writes: 50 GB
Default directory hash: half_md4
Directory Hash Seed: 4e7gds499c3-8532e0-452356c-432890c-d0fds43e2be81ee
Journal backup: inode blocks
Checksum type: crc32c
Checksum: 0xb054235dk
Wireless
I didn't end up having luck with iw, but I'm sure it is very useful. It seems I just wasn't able to interactively enter a password, so in the end I couldn't connect to WiFi. Worth looking at iw though.
sudo iw dev wlp0s20f3 scan
sudo iw dev wlp0s20f3 scan | grep SSI
sudo iw dev
sudo iw list
sudo iw wlp0s20f3 connect "Reed WIFI-2G"
See examples in man nmcli-examples. A lot of good information between this page and the SEE ALSO section at the bottom.
Network configurations
tree /etc/NetworkManager/
.
├── conf.d
│ └── default-wifi-powersave-on.conf
├── dispatcher.d
│ ├── 01-ifupdown
│ ├── 99tlp-rdw-nm
│ ├── no-wait.d
│ ├── pre-down.d
│ └── pre-up.d
├── dnsmasq.d
├── dnsmasq-shared.d
├── NetworkManager.conf
└── system-connections
├── Mi Casa.nmconnection
├── FAKE WIFI-2G.nmconnection
└── FAKE WIFI-5G.nmconnection
8 directories, 7 files
Terminal NetworkManager UI made using curses library can be installed and ran with the following commands
sudo apt install network-manager
nmtui
Gnome NetworkManager GUI for editing wireless and bluetooth connections using a GUI application build for Gnome desktops
sudo apt install network-manager-gnome
nm-connection-editor
Wifi can be toggled with wifi on and wifi off
wifi on
wifi = on
rfkill
ID TYPE DEVICE SOFT HARD
0 wlan phy0 unblocked unblocked
1 bluetooth hci0 unblocked unblocked
Connecting to WiFi
nmcli device wifi list
IN-USE BSSID SSID MODE CHAN RATE SIGNAL BARS SECURITY
* 40:B8:9A:D7:EC:AF FAKE WIFI-2G Infra 1 195 Mbit/s 100 ▂▄▆█ WPA2
40:B8:9A:D7:EC:B0 FAKE WIFI-5G Infra 149 405 Mbit/s 94 ▂▄▆█ WPA2
FA:8F:CA:95:43:9B Living Room Infra 6 65 Mbit/s 75 ▂▄▆_ --
FA:8F:CA:82:9D:D4 Family Room TV.b Infra 6 65 Mbit/s 57 ▂▄▆_ --
14:ED:BB:1F:44:6D Hi Infra 8 130 Mbit/s 57 ▂▄▆_ WPA2
14:ED:BB:1F:44:76 ATT9eu7M6L Infra 149 540 Mbit/s 44 ▂▄__ WPA2
4C:ED:FB:AD:D8:08 Fluffymarshmellow Infra 1 540 Mbit/s 30 ▂___ WPA2
70:77:81:DE:43:59 WIFIDE4355 Infra 1 195 Mbit/s 24 ▂___ WPA2
70:5A:9E:6C:D4:29 TC8717T23 Infra 6 195 Mbit/s 19 ▂___ WPA2
A8:A7:95:E8:68:82 Wildflower-2G Infra 1 195 Mbit/s 14 ▂___ WPA2
CC:2D:21:57:E0:71 Rudy Infra 6 130 Mbit/s 14 ▂___ WPA1 WPA2
CE:A5:11:3C:E4:C2 Orbi_setup Infra 9 130 Mbit/s 14 ▂___ --
A8:6B:AD:EB:B4:56 Gypsy-2 Infra 6 195 Mbit/s 12 ▂___ WPA1 WPA2
CE:A5:11:3C:EF:8E Orbi_setup Infra 9 130 Mbit/s 12 ▂___ --
Now bring up a connection with the access point we want, and pass the --ask flag to enter a password for authentication.
nmcli c up "FAKE WIFI-2G" --ask
Passwords or encryption keys are required to access the wireless network 'FAKE WIFI-2G'.
Password (802-11-wireless-security.psk): •••••••••••••••••••
Connection successfully activated (D-Bus active path: /org/freedesktop/NetworkManager/ActiveConnection/9)
Disable transmission devices with rfctl
rfkill list
0: phy0: Wireless LAN
Soft blocked: no
Hard blocked: no
1: hci0: Bluetooth
Soft blocked: yes
Hard blocked: no
Block WiFi
rfkill block wlan
Block Bluetooth
rfkill block bluetooth
Bluetooth
You can use bluetoothctl and bluetooth to control bluetooth devices
To check the status of bluetooth
rfkill
ID TYPE DEVICE SOFT HARD
0 wlan phy0 unblocked unblocked
1 bluetooth hci0 blocked unblocked
To turn bluetooth on (replace on with off to turn bluetooth off)
bluetooth on
bluetooth = on
kapper@xps:~/dot$ rfkill
ID TYPE DEVICE SOFT HARD
0 wlan phy0 unblocked unblocked
1 bluetooth hci0 unblocked unblocked
rfkill
ID TYPE DEVICE SOFT HARD
0 wlan phy0 unblocked unblocked
1 bluetooth hci0 unblocked unblocked
To scan and connect to devices, run bluetoothctl to enter a bluetooth shell
bluetoothctl
Agent registered
[bluetooth]#
Now, we can start a scan with scan on
[bluetooth]# scan on
Discovery started
[CHG] Controller AC:74:B1:85:27:98 Discovering: yes
[NEW] Device 6A:0C:07:6A:09:EC Inspire HR
[NEW] Device 48:FE:3D:EB:C8:C3 48-FE-3D-EB-C8-C3
[NEW] Device EB:28:A2:3E:99:3F One
After scanning for some time, type devices to see the devices discovered in a list. While doing this, we can stop the scan so our output isn't messed with.
[bluetooth]# scan off
Discovery stopped
[CHG] Controller AC:74:B1:85:27:98 Discovering: no
[CHG] Device 6B:98:C9:C1:86:6C RSSI is nil
[CHG] Device 59:A5:50:BA:7E:4E RSSI is nil
[CHG] Device 66:05:2D:A4:AF:D2 RSSI is nil
[CHG] Device 50:32:37:84:CB:D4 TxPower is nil
[CHG] Device 50:32:37:84:CB:D4 RSSI is nil
[CHG] Device 03:0D:0F:0F:E9:51 RSSI is nil
[CHG] Device 6A:81:34:01:76:C0 RSSI is nil
[CHG] Device EB:28:A2:3E:99:3F TxPower is nil
[CHG] Device EB:28:A2:3E:99:3F RSSI is nil
[CHG] Device 48:FE:3D:EB:C8:C3 RSSI is nil
[CHG] Device 6A:0C:07:6A:09:EC RSSI is nil
[bluetooth]# devices
Device 50:32:37:84:CB:D4 50-32-37-84-CB-D4
Device 90:DD:5D:98:3A:E7 90-DD-5D-98-3A-E7
Device F9:EB:78:07:17:4B Dell Keybd KB7221W
Device 28:11:A5:34:08:2C Dumbo
Device 34:82:C5:F8:04:F3 Sam
Device E6:4E:7A:3F:FD:E7 Dell Mouse MS5320W
Device F9:EB:78:08:17:4B Dell Keybd KB7221W
Device E6:4E:7A:57:FD:E7 Dell Mouse MS5320W
Device F9:EB:78:04:17:4B Dell Keybd
Device 6A:0C:07:6A:09:EC Inspire HR
Device 48:FE:3D:EB:C8:C3 48-FE-3D-EB-C8-C3
Device EB:28:A2:3E:99:3F One
Device 6A:81:34:01:76:C0 Family Room TV
Now, if we want to pair, simply type pair followed by the ID for the device
[bluetooth]# pair F9:07:78:DA:17:4B
Attempting to pair with F9:07:78:DA:17:4B
[CHG] Device F9:07:78:DA:17:4B Connected: yes
[agent] Passkey: 221692
[NEW] Primary Service (Handle 0x4461)
/org/bluez/hci0/dev_F9_07_78_DA_17_4B/service000a
00001801-0000-1000-8000-00805f9b34fb
Generic Attribute Profile
[NEW] Primary Service (Handle 0x4461)
/org/bluez/hci0/dev_F9_07_78_DA_17_4B/service000b
0000180a-0000-1000-8000-00805f9b34fb
Device Information
[NEW] Characteristic (Handle 0x4461)
/org/bluez/hci0/dev_F9_07_78_DA_17_4B/service000b/char000c
00002a29-0000-1000-8000-00805f9b34fb
Manufacturer Name String
[NEW] Characteristic (Handle 0x4461)
/org/bluez/hci0/dev_F9_07_78_DA_17_4B/service000b/char000e
00002a50-0000-1000-8000-00805f9b34fb
PnP ID
[CHG] Device F9:07:78:DA:17:4B UUIDs: 00001800-0000-1000-8000-00805f9b34fb
[CHG] Device F9:07:78:DA:17:4B UUIDs: 00001801-0000-1000-8000-00805f9b34fb
[CHG] Device F9:07:78:DA:17:4B UUIDs: 0000180a-0000-1000-8000-00805f9b34fb
[CHG] Device F9:07:78:DA:17:4B UUIDs: 0000180f-0000-1000-8000-00805f9b34fb
[CHG] Device F9:07:78:DA:17:4B UUIDs: 00001812-0000-1000-8000-00805f9b34fb
[CHG] Device F9:07:78:DA:17:4B ServicesResolved: yes
[CHG] Device F9:07:78:DA:17:4B Paired: yes
Pairing successful
[CHG] Device F9:07:78:DA:17:4B Name: Dell Keybd KB7221W
[CHG] Device F9:07:78:DA:17:4B Alias: Dell Keybd KB7221W
[CHG] Device F9:07:78:DA:17:4B Modalias: usb:v413Cp2511d0001
[Dell Keybd ]#
This device just happens to be a keyboard, so I'm asked to type the pascode 221692 on the keyboard, then press enter. Once I do this, the pair is completed and the devices are paired.
Next time you enable bluetooth with bluetooth on, and then you turn on this keyboard, the devices will automatically attempt to connect.
System Sensors
Your system likely has many sensors built in for displaying useful information on internal hardware status. For example, the commands below will help in finding the path to system temperature sensors.
user@host ~ $:sensors -f
coretemp-isa-0000
Adapter: ISA adapter
Package id 0: +80.6°F (high = +176.0°F, crit = +212.0°F)
Core 0: +73.4°F (high = +176.0°F, crit = +212.0°F)
Core 1: +73.4°F (high = +176.0°F, crit = +212.0°F)
Core 2: +69.8°F (high = +176.0°F, crit = +212.0°F)
Core 3: +68.0°F (high = +176.0°F, crit = +212.0°F)
acpitz-acpi-0
Adapter: ACPI interface
temp1: +82.0°F (crit = +221.0°F)
temp2: +85.6°F (crit = +221.0°F)
nouveau-pci-0100
Adapter: PCI adapter
GPU core: +0.97 V (min = +0.60 V, max = +1.27 V)
fan1: 691 RPM
temp1: +89.6°F (high = +203.0°F, hyst = +37.4°F)
(crit = +221.0°F, hyst = +41.0°F)
(emerg = +275.0°F, hyst = +41.0°F)
power1: 36.13 W (crit = 275.00 mW)
asus-isa-0000
Adapter: ISA adapter
cpu_fan: 0 RPM
We can see that the CPU and GPU temperature sensors are known to our system as coretemp-isa-0000 and nouveau-pci-0100, respectively. Run the command below to list the system path to all connected temperature devices by name, and cross-check these two outputs to gather the needed information for your sensors.
user@host ~ $:for i in /sys/class/hwmon/hwmon*/temp*_input; do echo "$(<$(dirname $i)/name): $(cat ${i%_*}_label 2>/dev/n
ull || echo $(basename ${i%_*})) $(readlink -f $i)"; done
acpitz: temp1 /sys/devices/virtual/thermal/thermal_zone0/hwmon0/temp1_input
acpitz: temp2 /sys/devices/virtual/thermal/thermal_zone0/hwmon0/temp2_input
coretemp: Package id 0 /sys/devices/platform/coretemp.0/hwmon/hwmon2/temp1_input
coretemp: Core 0 /sys/devices/platform/coretemp.0/hwmon/hwmon2/temp2_input
coretemp: Core 1 /sys/devices/platform/coretemp.0/hwmon/hwmon2/temp3_input
coretemp: Core 2 /sys/devices/platform/coretemp.0/hwmon/hwmon2/temp4_input
coretemp: Core 3 /sys/devices/platform/coretemp.0/hwmon/hwmon2/temp5_input
nouveau: temp1 /sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/hwmon/hwmon3/temp1_input
Displays
When attempting to manage displays, whether its the orientation or enabling / disabling, look to the man pages for xrandr. See the commands below for some examples.
# Output information on displays
xrandr
# List the output names for displays
xrandr --output
# Move DP-2 to the right of HDMI-1
xrandr --output DP-2 --right-of HDMI-1
``
#### Timezone
To see date / time, run `date`
To adjust local TZ settings, run `tzselect`. Pay attention to the final output of this tool as it will explain how to make your change permenant. For me, I had to add the following to the end of my `~/.profile` :
```bash
TZ='America/New_York'; export TZ
Memory
Some useful commands to find information on memory usage -
# Output various memory details
cat /proc/meminfo
#Can be used with grep, awk, etc for more specific output..
# ex) Show MiB of memory available
grep -w MemAvailable: /proc/meminfo | awk '{print $2 / 1024 "MiB"}'
Input Devices
Run the following to get information on input devices attached to the machine -
# In the output shown below, my keyboard is AT Translated Set 2 keyboard
xinput list
# Example output:
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ Elan Touchpad id=10 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Power Button id=6 [slave keyboard (3)]
↳ Power Button id=7 [slave keyboard (3)]
↳ Sleep Button id=8 [slave keyboard (3)]
↳ TOSHIBA Web Camera - HD: TOSHIB id=9 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=11 [slave keyboard (3)]
# Test the device..
xinput test "AT Translated Set 2 keyboard"
# Example output:
key release 36
key press 40
dkey release 40
key press 50
key release 50
# The output above shows me pressing / releasing keys in real time.
# Exit with CTRL-C
Power Supplies / AC Adapters
# List power supplies, AC adapters -
ls -l /sys/class/power_supply/
# Example output...
lrwxrwxrwx 1 root root 0 Mar 23 23:02 AC -> ../../devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:00/PNP0C09:00/ACPI0003:00/power_supply/AC
lrwxrwxrwx 1 root root 0 Mar 23 23:02 BAT0 -> ../../devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/device:00/PNP0C09:00/PNP0C0A:00/power_supply/BAT0
# Above, my battery is seen as BAT0, my AC port for charging is AC