upper and lower case together, not intermix dotfiles with normal filenames as a side effect of ignoring punctuation in the names (dotfiles are usually only shown if an option like -a is used), and the "$@" causes any parameters given to l to pass through as parameters to ls, so that all of the normal options and other syntax known to ls can still be used. The user could then simply use l for the most commonly used short listing. Another example of a shell script that could be used as a shortcut would be to print a list of all the files and directories within a given directory. #!/bin/sh clear ls -al In this case, the shell script would start with its normal starting line of #!/bin/sh. Following this, the script executes the command clear which clears the terminal of all text before going to the next line. The following line provides the main function of the script. The ls -al command lists the files and directories that are in the directory from which the script is being run. The ls command attributes could be changed to reflect the needs of the user. Note: If an implementation does not have the clear command, try using the clr command instead. Batch jobs Shell scripts allow several commands that would be entered manually at a command-line interface to be executed automatically, and without having to wait for a user to trigger each stage of the sequence. For example, in a directory with three C source code files, rather than manually running the four commands required to build the final program from them, one could instead create a script for POSIX-compliant shells, here named build and kept in the directory with them, which would compile them automatically: #!/bin/sh printf 'compiling...\n' cc -c foo.c cc -c bar.c cc -c qux.c cc -o myprog foo.o bar.o qux.o printf 'done.\n' The script would allow a user to save the file being edited, pause the editor, and then just run ./build to create the updated program, test it, and then return to the editor. Since the 1980s or so, however, scripts of this type have been replaced with utilities like make which are specialized for building programs. Generalization Simple batch jobs are not unusual for isolated tasks, but using shell loops, tests, and variables provides much more flexibility to users. A POSIX sh script to convert