bash

Question 1

prints lines 5-10 of the “examples” file

Answer 1

sed -n ‘5,10p’ example

Question 2

replace all instances of “old with “new” in the file “example”

Answer 2

sed -i s/old/new/g example

Question 3

Use the tab as a delimiter, then print the second field, a space-pipe-space string, and the first field from the file sample.

Answer 3

awk -F”\t” ‘{print $2 “ | “ $1} sample

Question 4

uniq

Answer 4

The uniq utility removes consecutive duplicates. This is why you almost always sort before using it.

Question 5

sort

Answer 5

The sort utility sorts output alphabetically. Use the -n option to sort numbers, so that you get 1, 2, 10, 20 instead of 1, 20, 2, 10.

Question 6

take all the lines from sample that contain a command, split them on the tab, print the second field, a space-colon-space, and then the first field. Then sort the lines in reverse numerical order and show me the first 3

Answer 6

grep ‘,’ sample | awk -F”\t” ‘{print $2 “ : “ $1 | sort -nr | head -3

Question 7

find all the files and directories that end with “.conf” in the /root directory

Answer 7

find /root -name “*.conf”

Question 8

find all the files and directories with the permissions of exactly 777 in the /home directory

Answer 8

find /home -perm 777

Question 9

find all directories in /home/myuser (includes hidden directories)

Answer 9

find /home/myuser -type d

Question 10

find all the files and directories owned by root in /home/myuser

Answer 10

find /home/myuser -user root

Question 11

combine the previous options - find in / all the files with 777 permissions, owned by root, and with a name ending with “.conf”.

Answer 11

find / -name “*.conf” -perm 777 -type f -user root

Question 12

print all files and directories below the current working directory

Answer 12

find

Question 13

find all files in /home with 777 permissions and change them to 644 permissions (DO NOT RUN THIS ON A CUSTOMERS SERVER!)

Answer 13

find /home -type f -perm 777 -exec chown 644 {} \;

Question 14

find all the files in /root with 777 permissions and show them in a long list format

Answer 14

find /root -perm 777 | xargs ls -l

Question 15

find all the messages in the queue that are from spammer@spam.com and delete them. (DO NOT RUN THIS ON A CUSTOMERS SERVER!)

Answer 15

exiqgrep -i -f “spammer@spam.com” | xargs exim -Mrm

Question 16

for each line in the file /etc/trueuserdomains, take the second word and print it to the screen (stdout)

Answer 16

for I in cat /etc/trueuserdomains | cut -d" " -f 2;do each $1 ;done

for i in $( cut -d “ “ -f 2 what ); do echo $i; done

Question 17

for each file in /var/cpanel/users, print the line with LEGACY_BACKUP in it, then print the username

Answer 17

for u in ls /var/cpanel/users;do BU$u” “grep LEGACY_BACKUP /var/cpanel/users/$u;each $BU;done

Question 18

If the file /var/cpanel/envtype contains exactly “kvm”, then print yes. If it does not, print no.

Answer 18

if [ “grep kvm /var/cpanel/envtype” = “kv” ];then echo “Yes”;else echo “No”;fi

Question 19

with less, search from the current position to the end of the document for lines with term, then second in them

Answer 19

/term.*second