Chapter $3$: The File System $89$catand moreare used to display the contents of a file. moresupports a number of internal commands that enable paging and searching for a pattern. Linux offers less as a superior pager.Rudimentary editing tasks can be performed with the picoeditor. The program uses the Control keys for all navigation and editing operations. You can perform cut$-$and$-$paste operations using the keys $[$Ctrl$-$k$]$and $[$Ctrl$-$u$],$ respectively.lpsubmits a job for printing which is actually carried out by a separate program. Linux and many UNIX systems use the lprcommand for printing. Both can be directly used to print Postscript documents.wccounts the number of lines, words, and characters. oddisplays the octal value of each character and is used to display invisible characters.The dos$2$unixand unix$2$doscommands convert files between DOS and UNIX. DOS files use CR$-$LF as the line terminator, while UNIX uses only LF$.$ The todosand fromdos commands also perform the same functions.gzipand gunzipcompresses and decompresses individual files $($extension: $.$gz$).$ tarcan archive a directory tree and is often used with gzipto create compressed archives $($extension: $.$tar.gz or $.$tgz$).$ zipand unzipuse $.$zip files. zipalone can create a compressed archive from directory structures $(-$r$).$ bzip$2$is better than zipand unzip $($extension: $.$bz$2).$SELF$-$TEST$3\mathrm{.}1$ How long can a UNIX filename be$?$ What characters can$$t be used in a filename?$3\mathrm{.}2$ State two reasons for not having a filename beginning with a hyphen$\mathrm{.}3\mathrm{.}3$ Name the two types of ordinary files, and explain the difference between them. Provide three examples of each type of file$\mathrm{.}3\mathrm{.}4$ Can the files noteand Notecoexist in the same directory?$3\mathrm{.}5$ Frame cdcommands to change from $($i$)/$var$/$spool$/$lp$/$adminsto$/$var$/$spool$/$mail$,($ii$)/$usr$/$include$/$systo $/$usr$\mathrm{.}3\mathrm{.}6$ Switch to the root directory with cd$,$ and then run cd $..$followedby pwd$.$ What do you notice?$3\mathrm{.}7$ Explain the significance of these two commands: ls $..$ ; ls $-$d $..\mathrm{.}3\mathrm{.}8$ Can you execute any command in $/$sbinand $/$usr$/$sbinby using the absolute pathname?$3\mathrm{.}9$ If the file $/$bin$/$echoexists on your system, are the commands echoand $/$bin$/$echoequivalent$?3\mathrm{.}10$ Look up the man pages of mkdirto find out the easiest way of creating this directory structure: share$/$man$/$cat$1\mathrm{.}3\mathrm{.}11$ If mkdir testfails, what could be the possible reasons?$3\mathrm{.}12$ How do you run lsto $($i$)$ mark directories and executables separately, $($ii$)$ also display hidden files?$3\mathrm{.}13$ What will cat foo foo foodisplay?$3\mathrm{.}14$ A file contains nonprintable characters. How do you view them?$3\mathrm{.}15$ How will you copy a directory structure bar$1$to bar$2?$ Does it make anydiffer$-$ence if bar$2$exists?