All scripts should be placed in the bin$/$ directory, in the user account$$s home directory. As a convenience,

this directory is included in the user$$s PATH. Scripts should have exactly the specified filename, and note that

only those files will be submitted, so your scripts will need to be $$self contained$.$

There are several test files in directories audio$/$ and playlists$/$ that may be helpful for testing scripts,

and examples are given below to clarify how your scripts should work. However, students are encouraged to

thoroughly test each script on other files before submitting $($the TA will use other files to test your scripts$).$

$5$ catm$3$u$.$sh

Write a Bash script named cat$\_$m$3$u$,$ sh that takes one or more M$3$U$-$format playlist files as arguments, and

displays the duration, title, and artist information for each track, and the total duration for the playlist.

$5\mathrm{.}1$ Input format

The script output should be based on the #EXTINF lines in the playlist files, which will always have the form

#EXTINF : seconds, trackinfo

where seconds is an integer and trackinfo is the remaining characters on the line. Your script should handle

MSU text files where line feeds may be indicated by a line$-$feed character $($LF$,$ or $\text{'}\backslash$

$^(2)),$ a carriage$-$return

character $($ CR $,$ or $\text{'}\backslash \backslash$r$^(\text{'})\text{'}),$ or a carriage$-$return character followed by a line$-$feed character. The playlists$/$

directory has examples of each.

$5\mathrm{.}2$ Output format

For each #EXTINF: line in an input playlist file, the script should write an output line containing a duration,

followed by two spaces, followed by the track information $($usually the title and artist$).$ After reading the

entire input file, the script should display a separator line containing $8$ : $=$ characters, followed by two

spaces, followed by $50^(2=>)$ characters. Then, the script should display the total duration of the playlist,

followed by two spaces, followed by the input file name with directory information stripped off. Finally, the

script should display a blank line.

Each duration should be right justified, take up exactly eight spaces, and have the form

$3$loti: ss

for durations under one hour, otherwise

h: man: ss

for durations of one hour or longer. You may assume that there will be no duration that exceeds $99$ hours.

In the above, $"$h$"$ indicates the number of hours, "sunn" indicates the number of minutes, and $"$ss$"$ indicates

the number of seconds, in a typical clock format: seconds are between $0$ and $59$ and always displayed as two

digits, minutes are between $0$ and $59$ and are displayed as one digit if and only if the duration is less than

ten minutes. hours are between $1$ and $99($because they are not displayed when $0)$ and are displayed as one

digit if and only if the duration is less than ten hours.

$5\mathrm{.}3$ Error handling

An appropriate error message should be displayed if the script is invoked with no command$-$line arguments.

An appropriate error message should be displayed for any input pathname that does not exist. All error

messages should be written to standard error.

$5\mathrm{.}4$ Examples

user$*$ cat$\_$n$3$u$,$sh

Usage: cat$\_$m$3$u$.$sh file file $...$

user $ pwd

$/$home$/$user

user$ cat$\_$m$3$u$.$sh playlists$/$B$*$ playlists$/$C$*$ playlists$/$D$*>$ list.txt

Couldn't find playlist playlists$/$C$*,$ skipping...

user$ cat list.txt

$3$:$59$ Brandenburg $1,$ first movement $-$ Joharn Sebastian Bach

$4$:$05$ Brandenburg $1,$ second movement $-$ Joharn Sebastian Bach

$4$:$25$ Brandenburg $1,$ third movement $-$ Joharn Sebastian Bach

$7$:$29$ Brandenburg $1,$ fourth movement $-$ Johann Sebastian Bach

$5$:$37$ Brandenburg $2,$ first movement $-$ Joharn Sebastian Bach

$4$:$28$ Brandenburg $2,$ second movement $-$ Joharn Sebastian Bach

$3$:$30$ Brandenburg $2,$ third movement $-$ Johann Sebastian Bach

$6$:$36$ Brandenburg $3,$ first movement $-$ Joharn Sebastian Bach

$0$:$13$ Brandenburg $3,$ second movement $-$ Joharn Sebastian Bach

$3$:$25$ Brandenburg $3,$ third movement $-$ Johann Sebastian Bach

$7$:$35$ Brandenburg $4,$ first movement $-$ Joharn Sebastian Bach

$2$:$49$ Brandenburg $4,$ second movement $-$ Johann Sebastian Bach

$5$:$23$ Brandenburg $4,$ third movement $-$ Johann Sebastian Bach

$9$:$58$ Brandenburg $5,$ first movement $-$ Joharn Sebastian Bach

$5$:$58$ Brandenburg $5,$ second movement $-$ Johann Sebastian Bach

$5$:$38$ Brandenburg $5,$ third movement $-$ Joharn Sebastian Bach

$7$:$10$ Brandenburg $6,$ first movement $-$ Johann Sebastian Bach

$4$:$32$ Brandenburg $6,$ second movement $-$ Johann Sebastian Bach

$6$:$12$ Brandenburg $6,$ third movement $-$ Joharn Sebastian Bach

$1$:$39$:$02$ Bach,$3$m$3$u