$2.$ Short answer $(3$ sentences maximum$)$:

Explain why the following code fragment will not work as expected:

pipe$($fd$)$;

switch$($cpid $=$ fork$())\{$

case $-1$: perror$("$fork failed"$)$; break;

case $0$:

while$($read$($fd$[0],$ buffer, sizeof$($buffer$))>0)\{$

printf$("$recv msg: $\%$s

$",$ buffer$)$;

$\}$

break;

default:

for$($i $=0$; i $<$ num$\_$msgs; i$++)\{$

write$($fd$[1],$ msg$,$ sizeof$($msg$))$;

$\}$

waitpid$($cpid$,$ NULL, $0)$;

break;

$\}$

Bash

$3.$ Write a bash function that will accept a two integer arguments, x and y$,$ returning

$0$ if x is a factor of y or $1$ if it is not. Invoke the function and print $$is a factor$$ or

$$not a factor$$ according to the result.

Sed

$4.$ Write a sed script that will:

a$.$ Remove the first number from a line, if it begins with a number

i$.$ For these lines, surround the entire line in $...$ tags

b$.$ Trim any repeat sequences of tabs and$/$or spaces down to a single space

c$.$ Replace all sequences of digits that reside immediately prior to a

hyphen with a single $$x$.$

Example input:

$25323$xr output freq $150\mathrm{.}32$

$8892$vfr outbound N$2137$ cs $12-01-1990$

ifr inbound N$9983$ heavy

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