Lab 13: Further Practice

Due Tuesday, December 5


As usual, place the commands you used to solve each of the 5 problems into a file called lab13. This is intended as practice.
  1. Write a command that prints out the number of directories listed in the PATH variable. Directories are separated by colons, but there is not a leading or trailing colon.
  2. Create a command that prints out the names of the 10 largest files in the current directory, in order from largest to smallest, with human-readable sizes.
  3. Make 100 files, numbered 1-100, each containing a single word. You might want to test this in a directory other than your home directory (make one for the purpose). A loop will work here, but mkdir and {} ranges will also work.
  4. Running "service --status-all" will show the status of all services on isoptera. Are more service running (+) or stopped (-)? Have your command print the number of each. It does not need to determine which number is greater.
  5. /proc/interrupts will show what each interrupt on the system is used for, and the number of interrupts handled by each processor. On a computer without many processors, it looks like this: 
               CPU0       CPU1       
  0:    7449584    5652603   IO-APIC-edge      timer
  1:      18591      16694   IO-APIC-edge      i8042
  8:          1          0   IO-APIC-edge      rtc0
  9:     102720     102820   IO-APIC-fasteoi   acpi
 12:     220865     200951   IO-APIC-edge      i8042
 14:     113535     110905   IO-APIC-edge      ata_piix
 15:          0          0   IO-APIC-edge      ata_piix
 16:          0          0   IO-APIC-fasteoi   uhci_hcd:usb3, yenta
 17:          1          1   IO-APIC-fasteoi   firewire_ohci, uhci_hcd:usb4
 18:          0          0   IO-APIC-fasteoi   mmc0, uhci_hcd:usb7, r592, r852
 19:          0          0   IO-APIC-fasteoi   ehci_hcd:usb6
 20:         72         66   IO-APIC-fasteoi   uhci_hcd:usb1
 21:          0          0   IO-APIC-fasteoi   uhci_hcd:usb2
 22:          1          2   IO-APIC-fasteoi   ehci_hcd:usb5
 23:          0          0   IO-APIC-fasteoi   i801_smbus
 40:          0          0   PCI-MSI-edge      PCIe PME
 41:          0          0   PCI-MSI-edge      PCIe PME
 42:          0          0   PCI-MSI-edge      PCIe PME
 43:          0          0   PCI-MSI-edge      PCIe PME
 44:          0          0   PCI-MSI-edge      PCIe PME, pciehp
 45:          0          0   PCI-MSI-edge      PCIe PME
 46:         30          2   PCI-MSI-edge    
 47:     431806     422206   PCI-MSI-edge      ahci
 48:     590550     480638   PCI-MSI-edge      snd_hda_intel
 49:       2126    8808762   PCI-MSI-edge      iwl3945
 50:      64579      48729   PCI-MSI-edge      nvidia
NMI:       8278       8520   Non-maskable interrupts
LOC:    5684955    6683330   Local timer interrupts
SPU:          0          0   Spurious interrupts
PMI:       8278       8520   Performance monitoring interrupts
IWI:          2          0   IRQ work interrupts
RTR:          0          0   APIC ICR read retries
RES:    2932614    2979736   Rescheduling interrupts
CAL:       1542       1783   Function call interrupts
TLB:     620032     613178   TLB shootdowns
TRM:          0          0   Thermal event interrupts
THR:          0          0   Threshold APIC interrupts
MCE:          0          0   Machine check exceptions
MCP:        766        766   Machine check polls
HYP:          0          0   Hypervisor callback interrupts
ERR:          0
MIS:          0
    On isoptera, this file is made nearly unreadable by the large number of CPUs on the system. Print out the file, without any of the CPU columns, but with the interrupt number (number before the colon), and the interrupt use (the text at the end) still intact and lined up correctly.
Turn in your lab by creating a file named "lab13" with no extension in your home directory, with permissions set so that only you can view the file. This assignment is worth 35 points, 5 from correct naming, 5 from correct permissions, and 5 from each of the problems above. As a reminder, you can set the permissions correctly with this line:
chmod 600 lab13