Question

5. Which command below deletes lines which has only letters? a. sed '/[a-Z]*$/d' file b.sed [a-Z]+S/d' file c. sed 'IMa-zA-Z]*$/d' file d. sed '/[a-zA-Z]*$/ d' file e. None of above

Answer 1

answer is option c.

sed '/[a-zA-Z]*$/d' file

The alternative of the above command is

sed -i '/[a-z]*$/d' file .

the above command takes -i for ignoring the case.

sed is a command used for replacing/deleting lines in a file.

we write the input(what to delete/replace ) in ( between two slashes : '/ /')

after the slash d is for deleting.

for replacing we use r.

In the out of given the suitable answer is option c.

^ indiacates the begining of the line.$ Indicates the end of the line.In between begining and ending the line we need to delete the alphabets .So we write '[^a-zA-Z]$' and slash(/) is used for sed command and d option for deleting the matched pattern.