Answer the following questions about regular expression, give an example if necessary. • what is the difference between ab.cd and ab*cd? • what is the difference between ab.*cd and abb*cd ? • what is the difference between ^abc and ^abc$? • what is the difference between [abc]d and [^abc]d? • What is the difference between [A-Z][_a-zA-Z0-9]* and [A-Z_][a-zA-Z0-9]*? (Note the regular expression “x*$” could be described as a line has “zero or more x at the end of the line”.) c University of Southern Queensland 12 CSC2408—Software Development Tools Question 3. (10 marks) • Give the command-line of using find to list all the files having specific username in the current directory • Give the command-line of using find to list all the subdirectories in the current directory • Use find to produce a long ls listing of all files in /usr/bin that are more than 750Kb long. Give all the arguments and options in the following command-line find ..... -exec ls -l {} \; Note that pay special attention to the arguments or options. The semicolon must be escaped, but not the {}. Question 4. (10 marks) Create a big file (If you don’t know how to create a big file, try ls -l /usr/bin > bigfile). Create two copies of it using cp, and call them big1 and big2. • Give the command-line of compressing big1 using gzip (should produce big1.gz). • Compress big2 using bzip2(should produce big2.bz2). • Give the command-line of comparing the sizes of the compressed files (big1.gz and big2.bz2) and the original (bigfile) using ls -l • Give the command-line of checking the file type of compressed files and the original. • Give the command-line of displaying the contents of big1.gz using zcat and big2.bz2 but using bzcat without uncompress them. (You may pipe the output to head -10 to avoid lots of output). Question 5. (10 marks) • Use tar to create an archive (don’t use the z or j option) of all the files in the current directory. • Compress the tar file with gzip. c University of Southern Queensland CSC2408—Software Development Tools13 • View the contents of archive with gunzip -c gzipped-tar-file | tar tfv - • View without using gunzip but use the tar instead. (Hint: find the right option to use from the man page). • Create a subdirectory of the current directory. • Use tar to unpack the archive into that directory at the current directory. Question 6. (10 marks) Assume you have a text file called file. Explain the following commandlines. 1. sed "s/the/a/g" file 2. sed -n "s/[A-Z]/&/gp" file 3. sed "32,45 s/[()]//g" file 4. sed "/^$/d" file 5. sed "s/\([0-9]\)-\([0-9]\)/\1\2/g" file 6. sed "80q" file For example, sed ’s/fox/ox/g’ file will replace all occurance of fox with ox and not the just the first one in file

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