Question

Write a script using simple shell commands. The script takes a command line argument that specifies a directory dir. The script first changes directory to dir, then prints the following in sequence:

(a) A line starting “Current date and time: ”. Then on the same line, the current time and date.

(b) A line starting “Current directory is : ”. Then, on the same line, the absolute pathname of the current working directory.

(c) An empty line

(d) The line “--- 10 most recently modified directories ---”

(e) the 10 most recently modified subdirectories in the current directory in long listing format (most recent first)

(f) An empty line

(g) The line “--- 6 largest files ---”

(h) The 6 largest files in the current directory in long listing format (largest file last)

(i) An empty line, followed by a line of 70 equal signs

Answer 1

Hi, I got your question. I have created a script using simple shell commands to complete the task.

Task 1: Change directory to the given command line argument. To do so, I have used if statement

if [ -d "$1" ]; then

cd $1

This checks where the given argument is a directory and changes to the given directory else print "Directory does not exist!!!"

Task 2: Current date and time. This can be done easily by date command but I have used date +"%D %T" to print current date and time.

Task 3: Current directory. This can be easily done by using pwd command. It returns the complete address to the current directory.

Task 4: 10 Most recently modified files. I have done this with the help of ls -ltp | grep "/" | head -n 10 command

ls: to list

-ltp: long list format with time-based output

grep "/" : to print only directories

head -n 10: to print top 10 of the results.

Task 5: 6 largest files. I have done this with the help of find . |ls -l | grep -Ev "total" |sort -nr|head -n 6 command

find . : to find in the current directory

ls -l: to get result in long list format

grep -Ev "total": to remove the line have "total" keyword in them

sort -nr: to sort the result on the basis of size.

head -n 6: to print top 6 of the results.

If to find the largest file and print in the long list is not required then:

find . -printf '%s %p\n'|sort -nr|head is command will give the best result.

find . -maxdepth 1 -printf '%s %p\n'|sort -nr|head this command will restrict find to max-depth of 1 sub-directory only

The final script is:

#!/bin/bash
if [ -d "$1" ]; then
cd $1
   echo "Current date and time: $(date +"%D %T")"
   echo "Current directory is: $(pwd)\n"
   echo "--- 10 most recently modified subdirectories ---"
   ls -ltp | grep "/" | head -n 10
   echo "\n"
   echo "---6 largest files ---"
   find . |ls -l | grep -Ev "total" |sort -nr|head -n 6
   echo "\n"
   for i in `seq 1 70`;
   do
   echo "*\c"
   done
   echo "\n"
else
echo "Directory not exist!!!"
fi

Below are the images of the script in vi editor and leafpad.

Output of the scripts:

Hope this would help you. If you have any further query feel free to ask.