Lab 0: Using the Terminal CS220, Summer 2013 Tyler Stachecki Shell ● Text-based, command interpreter. – sh, bash, csh, tcsh, ksh, … ● bash, csh most widely used – Differences? Syntax. ● Same set of system commands available regardless of which shell you choose. – Default is csh on our systems. Shell ● Filesystem Organization – Broken into directories and files. – Outermost directory is always / (root) – External drives, other devices are 'mounted' as directories somewhere within the filesystem. ● mounts can exist within mounts – Your home directory is always represented by ~ ● On most systems, this maps to /home/username Navigating Around ● pwd: print working directory – Prints the directory that you're “in”. ● cd <arg>: change directory to <arg> – Sets the working directory to <arg> ● <arg> is relative to current directory – “..” maps the parent directory – “.” maps to the current directory – “~” maps to your home directory Navigating Around ● pushd <arg>: push working onto directory stack, and change directory to <arg> ● popd: pops directory off directory stack, changes working directory to popped value Navigating Around ● ls <arg>: List directory contents – How would you list current directory contents? ● What happens when you pass no arguments? ● Some commands also have switches or options that you can pass that control the tool. – What does ls -l do? Creating Files ● Linux has a wide variety of text editors. – Try pico <filename> or nano <filename> – Once you get into the habit of using these tools, you might want to look into vim or emacs ● Syntax highlighting ● Regular expressions ● Shell interface within editor ● ... Getting Help ● man <command>: Opens the manual page for a given command. – Try man man ● Most tools also provide a --help or -h switch that outputs their usage. Manipulating Files, Directories ● mkdir, rmdir ● cp, rm, mv ● Use man to figure out what they do (if you can't tell by their names), and how to use them. Some Development Tools ● gcc: The GNU C compiler ● g++: The GNU C++ compiler – gcc/g++ -E will invoke the preprocessor (cc1) – Can also call cc, cxx, and cc1 directly. ● as: The assembler – gcc/g++ -S will also invoke the assembler. ● ld: The linker – If you don't specify gcc/g++ -c, then the tools will compile, assemble, and link all the C files you pass as arguments for you. “Redirection” ● By convention, most programs read from stdin, or standard input. By default, the terminal maps this to your keyboard! ● Your terminal outputs the contents of stdout and stderr. Most programs, also by convention, write their output to these files. ● You can redirect the input and output to your program so that other files are used in place of stdin, stdout, and stderr. “Redirection” ● To redirect stdin, use the < symbol in combination with a filename. – ./my_program_that_reads_input < input_data ● To redirect stdout, use the > symbol in combination with a filename. – ls -l > directory_contents.txt ● To redirect stderr, use 2> in combination with a filename. – ls -l 2> directory_contents.txt Lab Assignment ● In your own words, describe the function of the following tools in two or more sentences. Be descriptive, and do not verbatim copy the man pages or from these slides. – cd, pushd, popd, cat, less, ls, chmod, chown, mkdir, rmdir, rm, cp, mv, tar, gcc, g++, as, and ld. – Name the file tools.txt Lab Assignment ● Write a C program that outputs your name. Name the file name.c. ● Generate name.i (preprocessor output), name.S (compiler output), name.o (assembler output), and name (executable). Include all of them in your submission. Lab Assignment ● Put all of the files in a directory: – yourBUid_cs220_lab0 ● Create a tape archive (tarball), compress it, and submit it via Blackboard. – tar -czvf yourBUid_cs220_lab0.tgz \ yourBUid_cs220_lab0 .