UNIX for Dummies Questions & Answers

#!/bin/bash
 
echo
echo "User ID?"
echo
read INPUT
 
TEMPIN=$INPUT;
 
TEMPTN=`grep ":${TEMPIN}:" /etc/group |cut -d: -f3`;
 
TEMPST=`grep ":${TEMPIN}:" /etc/group |cut -d: -f1`;
 
echo "True number ${TEMPTN}"
echo "True String ${TEMPST}"
echo "Input ${TEMPIN}"
 
if [ $TEMPNT==$TEMPIN ]; then
 
 
           echo  
           echo "GID        : ${TEMPTN}"
           echo "Group name : ${TEMPST}"
           echo
           echo "Already exists, do you want to use this group"
           echo
           echo "<y> or <n>"
           read INPUT
 
                 echo        
                 if [ ! $INPUT = "n" ]; then
                 GROUP_ID=${TEMPIN};
                 fi
fi
 
if [ ! $TEMPNT==1$TEMPIN ]; then
 
 
     echo
     echo "Group ID ${TEMPIN} does not exist"
     echo "would you like to create it?"
     echo
     echo "<y> or <n>"
     echo
     read INPUT
     echo
           if [ ! $INPUT = "n" ]; then
                 echo
                 echo "Enter group name"
                 read NAME
                 echo              
                 GRP=$NAME;
                 GID=$TEMPIN;
 
                       else
                       echo "Setup cannot contine without a specified group!"
                       exit
           fi
fi

if [ "$TEMPTN" == "$TEMPIN" ]
then
  do_stuff
fi

#!/bin/sh
# Using sh rather than bash as you don't need the extra functions in bash when sh will do the job :)

# Will either exit with a non-zero (error) return code or will populate the GID and GRP variables with a group and groupname.
# If GRP is zero length, the group already exists, if it contains text, it must first be created.

GRP=""  # Make sure it's not still set from a previous run
echo Group ID?"
read GID

groupname=`grep ":$gidin: /etc/group | cut -d ':' -f 1`

if [ -n "$groupname" ]
then
  # The group already exists
  echo "$groupname (GID: $GID already exists."
  echo "Do you want to use this group? (y/n)"
  read input
  if [ ! "$input" == "y" ]
  then
    echo "Exiting..."
    exit 1
  fi
else
  # The group does not yet exist
  echo "Group id $GID does not already exist."
  echo "Would you like to create it? (y/n)"
  read input
  if [ "$input" == "y" ]
  then
    echo "Enter group name"
    read GRP
  else
    echo "Exiting..."
    exit 1
  fi
fi

# Rest of code here
if [ -z "$GRP" ]
then
  # create the group
fi

# Code to add username to groupname $GRP, gid $GID here