#include #include #include int main() { int pid,status; char comd[20];pid=fork(); if(pid==0) { printf("child processn"); while(strcmp(comd,"exit")!=0) { printf("[user@localhost~]$"); gets(comd); system(comd); } exit(0); } else { wait(&status); printf("parent processn"); } } ****************************************…

#!/bin/sh str=tanu echo “string:$str” echo “lengh of string:” z=`expr “$str”:’.*’` echo $z echo “substring is” z=`expr “$str”:’.*(…)’` echo $z echo “position of character n is” z=`expr “$str”:’[^n]*n’` echo $z *******************…

#!/bin/sh if [ $# -ne 1 ] then echo " no arguments " exit fi curdir=`pwd` for dir in `echo $1 | tr '/' ' ' ` do if […

echo "program name: $0" if [ $# -eq 0 ] then exit fi echo "no: of arguments: $#" echo "the input arguments are" num=1 for i in "$@" do echo…

clear echo "Menu " echo "1. Copy a File " echo "2. Remove a file " echo "3. Move a file" echo "4. Quit" echo "Enter ur Choice c" read…

#!binsh echo "options are :n+:addn-:substractn*:multiplyn/:divide " echo "enter the 2 nos " read a read b echo "nenter your choice " read ch case $ch in '+') y=`expr $a +…

#!binshecho "enter the string"read stringif [ -z "$string" ]thenecho "null string"elsez=`expr "$string" : '.*'`echo "string length is $z"fiif [ $z -ge 6 ]thenecho "first 3 characters"z=`expr "$string" : '(...).*'`echo "$z"echo…

display_perm() { r=`ls -l $1 | cut -c 2` w=`ls -l $1 | cut -c 3` x=`ls -l $1 | cut -c 4` echo "owner permissions" if [ "$r" =…

A shell program to search a pattern in a file that will take both pattern and file name from the command line arguments. Write a second shell program to read the pattern…

#!/bin/sh echo "Enter the year" read year x=`expr $year % 400` y=`expr $year % 100` z=`expr $year % 4` if [ $x -eq 0 ] || [ $y -ne 0…