While running Linux, if you want to list the contents of a folder in a vertical list format, just use the ls command with these switches.
jason@ubuntu:~$ ls -luh --color=yes total 48K drwxr-xr-x 2 jason jason 4.0K Dec 15 03:03 Desktop drwxr-xr-x 2 jason jason 4.0K Nov 29 17:00 Documents drwxr-xr-x 2 jason jason 4.0K Nov 29 17:29 Downloads -rw-r--r-- 1 jason jason 8.8K Nov 25 20:57 examples.desktop drwxr-xr-x 2 jason jason 4.0K Nov 25 21:18 Music -rw-r--r-- 1 jason jason 459 Dec 7 17:21 partsize drwxr-xr-x 2 jason jason 4.0K Nov 25 21:19 Pictures drwxr-xr-x 2 jason jason 4.0K Nov 25 21:18 Public drwxr-xr-x 2 jason jason 4.0K Dec 15 03:03 Templates drwxr-xr-x 2 jason jason 4.0K Nov 25 21:18 Videos |
then you get the directory listing with human readable file sizes instead of being listed in bytes.
To list the partitions on a disk, just type
sudo fdisk -l /dev/sda |
for example and it will list the partitions on the device. You need superuser priviledges to run this command. Then you get the output below.
jason@ubuntu:~$ sudo fdisk -l /dev/sda [sudo] password for jason: Disk /dev/sda: 21.5 GB, 21474836480 bytes 255 heads, 63 sectors/track, 2610 cylinders, total 41943040 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x000d5c84 Device Boot Start End Blocks Id System /dev/sda1 * 2048 39845887 19921920 83 Linux /dev/sda2 39847934 41940991 1046529 5 Extended /dev/sda5 39847936 41940991 1046528 82 Linux swap / Solaris |
A very useful command. This is useful when I am double checking which partition to install Linux to on my hard drive so I do not overwrite the wrong partition.
Get CPU information from your machine using the cat /proc/cpuinfo command.
jason@ubuntu:~$ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 60 model name : Intel(R) Core(TM) i5-4670K CPU @ 3.40GHz stepping : 3 microcode : 0x9 cpu MHz : 3399.030 cache size : 6144 KB physical id : 0 siblings : 1 core id : 0 cpu cores : 1 apicid : 0 initial apicid : 0 fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc aperfmperf eagerfpu pni pclmulqdq ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm ida arat xsaveopt pln pts dtherm fsgsbase tsc_adjust bmi1 avx2 smep bmi2 invpcid bogomips : 6798.06 clflush size : 64 cache_alignment : 64 address sizes : 42 bits physical, 48 bits virtual power management: |
List all users on your Linux machine.
jason@ubuntu:~$ sudo cut -d: -f1 /etc/passwd [sudo] password for jason: root daemon bin sys sync games man lp mail news uucp proxy www-data backup list irc gnats nobody libuuid syslog messagebus usbmux dnsmasq avahi-autoipd kernoops rtkit saned whoopsie speech-dispatcher avahi lightdm colord pulse hplip jason ntp |
List all users with passwords in the /etc/shadow file.
jason@ubuntu:~$ sudo awk 'length($0)>42' /etc/shadow root:$6$94h9BlHF$xGJjZIKlOVfuDc4V7pXzc7Qhy3YUjthc3Qusj5axc6l1HpUFgCNbk0MybBKfP7Oj9zraEGV6w8aEA5gHuipcW.:16784:0:99999:7::: jason:$1$/.DJdFfa$AdDAUD25jfdDBtS4vxfL5/:16765:0:99999:7::: |
List all users on your Linux machine that can actually login, not system users.
jason@ubuntu:~$ sudo awk -F':' '$2 ~ "\$" {print $1}' /etc/shadow root jason |
Another way to list all users on your system with passwords, with the exception of the root user.
jason@ubuntu:~$ sudo awk -F'[/:]' '{if ($3 >= 1000 && $3 != 65534) print $1}' /etc/passwd jason |
Another version. This will list all users with a UID over 500.
jason@ubuntu:~$ sudo awk -F'[/:]' '{if ($3 >= 500 && $3 != 65534) print $1}' /etc/passwd jason |
Very nice and Informative, preparing for Linux Certification, wanted to learn some Linux Commands, can anyone suggest me some books and videos?