Chopping strings

Question 1

Basename

Answer 1

>basename /etc/sysconfig/iptables

iptables

Question 2

Dirname

Answer 2

>dirname /etc/sysconfig/iptables

/etc/sysconfig

Question 3

Chopping substrings - REMOVE longest from beginning with wild card

Answer 3

>MYVAR=foodforthought.jpg

>echo ${MYVAR##*fo}

rthought.jpg

• The { } are used to define the string in the variable MYVAR
• The 2 # indicate the fact we are looking for the longest string containing the wild card
• The string following the * specify the wild card string. in this case fo
• So we would like to display the portion of $MYVAR from which the longest string starting from the left and ending in fo is removed

Question 4

Chopping substrings - REMOVE shortest from beginning with wild card

Answer 4

>MYVAR=foodforthought.jpg

>echo ${MYVAR#*fo} odforthought.jpg

• The { } are used to define the string in the variable MYVAR
• The 1 # indicate the fact we are looking for the longest string containing the wild card
• The string following the * specify the wild card string. in this case fo
• So we would like to display the portion of $MYVAR from which the shortest string starting from the left and ending in fo is removed

Question 5

Using # versus %

Answer 5

truncates from beginning of string % truncates from end of string

Question 6

DISPLAY by specifying starting point and count numbers of characters to take out

Answer 6

>EXCLAIM=cowabunga

>echo ${EXCLAIM:0:3}

cow

• started at 0, the left of the string, and DISPLAY the first 3 chracaters

>echo ${EXCLAIM:3:7}

abunga

• start at the third characters and display seven following characters ALWAYS TEST THESE BEFORE USING