Ryan Pilatowski
IT 250 linux
1/23/13
1. A. make the file executable : $ chmod +x filename.sh
Run the script: $ ./filename.sh
B. it reads the name from stdin and cats it to journal-file rather than stdout.
2. If you replace "$@" with "$*" in the out script, cat or less would be given a single argument: a list of all files you specified on the command line enclosed within single quotation marks. This list works when you specify a single filename. When you specify more than one file, the shell reports No such file or directory because there is not a file named the string you specified on the command line (the SPACEs are not special characters when they are enclosed within single quotation marks). 3. Sort,tsort diff, patch,diff3, sdiff, cmp, comm, uniq, expand, unexpand, cut, colrm, paste, join, head, tail, grep, look, sed,awk, sed, awk, wc, tr, fold, fmt, ptx, column, nl, pr, gettext, iconv, recode, groff, gs, TeX, lex, yacc, 4. $ function pores } * Chmod u+x $1 * } * a. When might such a function be useful? * When you are writing many shell scripts, it can get tedious to give many * chmod commands. This function speeds up the process. * b. Revise the script so that it takes one or more filenames as arguments * and adds execute permission for the user for each file argument. * $ function perms { * > chmod u+x $* * > } * c. What can you do to make the function available every time you log in? * Put the function in your .bash_profile, .bash_login, or .profile file to make * it available each time you run a log in (using bash). * d. What if, in addition to having the function available on subsequent * login sessions, you want to make the function available now in your * current shell? * Use source to execute the file you put the function in, for example, * $ source .bash_profile 5. A shell function will do nothing unless it is explicitly called by other code, typically in a shell script. A shell script is a runnable, executable process, which can call other shell scripts and/or functions.

The question might be worded backwards - it is necessary to write shell functions for shell scripts when certain logical functionality is required to be performed multiple times. Consider a shell function equivalent to a program subroutine - they operate the same way. 6. There are many ways to solve this problem. Following, the listdirs script uses file to identify directory files and grep to pull them out of the list.
Finally, sed removes everything from file’s output including and following the colon.
$ cat listdirs file "$@" | grep directory | sed 's/:.*//'. 7. while true do date sleep 15
done