SLG ULI101 Week 12 - Bash II

In a Bash script, how do we use grep without outputting anything to the terminal?

• grep "REGEXP" > /dev/null 2>&1

• grep "REGEXP" > /dev/null

• grep "REGEXP"

• grep "REGEXP"

  $?

If we wanted to check if the number of arguments doesn't equal 1, we write...

• if [ $# -ne 1 ]

• if [ $? -ne 1 ]

• if [$# -ne 1]

• if [ $1 -ne 1 ]

What is the significance of double parenthesis in Bash?

• Allows us to do mathematical operations

• Allows us to concatenate strings

• No significance over single ()

• None of the above

If we wanted our echo to overwrite the same line (so no new lines) we write...

• echo -n "BLAHBLAH"

• echo -ne "BLAHBLAH\r"

• echo -ne "BLAHBLAH\n"

• echo -ne "BLAHBLAH"

If we wanted to loop through each argument we would write...

• for thing in $@

• for thing in $#

• for thing in $1 $2 $3

• for thing in $args

$@ returns?

• all arguments separated by a space

• all arguments with no spaces

• the number of arguments

• none of the above

To save the output of a command to a variable we write...

• today=$(date -I)

• today=date -I

• date -I > $today

• echo date -I

  read today

If we wanted to check if a file exists we write...

• if [ -f $fileInQuestion ]

• if [ $fileInQuestion ]

• if [ $fileInQuestion -eq 0 ]

• echo $fileInQuestion

What is the output from issuing:

./walkthru1.bash

What is the output from issuing:

./walkthru2.bash apple orange banana