Lab One

1.1

  • ls -r

1.2

  • ~ returns to your home directory
  • ~hpotter goes into hpotter's home directory

1.3

  • head -10 (or 25) FILENAME for the first 10 or 25 lines of a file
  • tail -12 FILENAME for the last 12 lines of a file

1.4

  • adds a directory to the top of the remembered directory stack (or moves that order around)
  • removes the top directory in the stack
  • shows all of the directories in the remembered stack
  • push and pop are names used for adding and removing things from lists

1.5

  • lpr FILENAME sends it to the printer
  • lpq displays the jobs and their status on the printer queue

1.6

  • use man COMMAND or help COMMAND or --help or use google/wikipedia/other web resources.

1.7

  • diff -B to ignore blank lines in the text files
  • diff -i to ignore case differences in file contents

1.8

  • anyone can read earth.txt, but only Alan Turing can write it.
  • it was last changed at 9:17 on July 12
  • the command to allow others to write the file would be chmod o+w earth.txt

1.9

  • rm a??.txt

1.10

  • you would check by ls -l and the last set of 3 for Dr. Evil's permissions
  • to get rid of his permissions chmod -R o-rwx

1.11

  • cd HOME changes directories to the first directory it finds named 'HOME' while cd $HOME changes directories to the location specified by the variable HOME which is ~

1.12

  • grep looks for words in files

1.13

  • analyze FILE | head -10 > tmp.txt to send the stdout of analyze to the stdin of head then > to send it to tmp.txt

1.14

  • to append it to the listing you use >> instead of >

1.15

  • find . -type "d" | wc

1.16

  • rm *.ch deletes all files ending in .ch while rm *.[ch] removes everything that ends in .c or .h

1.17

  • ps aux | grep "bash" finds instances of bash in ps

1.18

  • tar -cf NAME.tar items

1.19

  • you would use diff OLD NEW to find the differences

1.20

  • passwd

1.21

  • grep -n for line number -x for matches

1.23

  • alias sets one command as another