If statement arguments


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# 1  
If statement arguments

I'm stuck on a particular problem and need some guidance. I have a file with a name and a phone number in it (teledir.txt). I need to do a $# in a separate script to take a positional parameter and check to see if it is in the file. To quote the question:



Code:
If one argument is supplied, check to see if it starts with a digit, then search for it in the teledir.txt file. If it doesn't exist, echo "Doesn't Exist".


If argument starts with a letter, search for it in the file, If it doesn't exist, echo "Name does not exist" 



If two arguments are supplied, set the search_pattern to be “name: number”, and search it in the file. 
  • If it is not found, echo “Adding entry”, and append to the file/variable.
  • Otherwise, echo that “Entry exists”

I am only two weeks into learning the command line prompt. This is the code I have gotten so far but I am stuck on where to go from here. Not sure if this will even work. Any pointers please!!!


Code:
#!/bin/bash

name=$1
number=$2


if [ $# -eq 0 ]; then
        echo "Two arguments are expected in the form of ./scriptname [name number]"
fi

if [ $# -eq 2 ]; then
        grep -qiw "$name\|$number" teledir.txt
        echo "$name or $number exists"
fi

# 2  
In bash you can check whether a variable starts with a number like so:
Code:
if [[ $somevar == [0-9]* ]]; then

You can check if it begins with a letter like this:
Code:
if [[ $somevar == [[:alpha:]]* ]]; then

# 3  
Quote:
Originally Posted by Eric7giants
Code:
if [ $# -eq 2 ]; then
        grep -qiw "$name\|$number" teledir.txt
        echo "$name or $number exists"
fi

Code:
if [ $# -eq 2 ]; then
        if grep -qiw "$name\|$number" teledir.txt; then
            echo "$name or $number exists"
        fi
fi

# 4  
Thanks for all of the help. I truly appreciate it. I am running into one more issue. When I enter a positional parameter of a name that I know is in the file. It still outputs as name does not exist. This is the code I have so far:


Code:
#!/bin/bash

name=$1
number=$2

if [ $# -eq 0 ]; then
        echo "Two arguments are expected in the form of ./scriptname [name number]"
fi


if [ $# -eq 1 ]; then
        if grep -qiw "$name | $number" teledir.txt; then
                echo "$name exists"
        else
                echo "Does Not Exist"
        fi
fi

# 5  
Quote:
if grep -qiw "$name | $number" teledir.txt; then
Code:
if grep -qiw "$name\|$number" teledir.txt; then

and with this design, 2 parameters are needed and not equal to an empty string
Otherwise
Code:
if [ $# -eq 1 ]; then
    if grep -qiw "$name" teledir.txt; then
        echo exists
    else
        echo no exists
    fi
fi

--- Post updated at 21:16 ---

Code:
#!/bin/bash
if [ $# -lt 2 ]; then
        echo 2 parameters required
        exit
else
        if [ -z "$1" -o -z "$2" ]; then
                echo The parameter cannot be an empty string
                exit
        fi
        if [ -n "${1//[[:alpha:]]}" -o -n "${2//[0-9-]}" ]; then
                echo Invalid parameters
                exit
        fi

fi

if grep -qiw "$1\|$2" teledir.txt; then
        echo "$1 or $2 exists"
else
        echo "Does Not Exist"
fi


Last edited by nezabudka; 10-26-2019 at 03:41 PM..
# 6  
The issue I'm running into is that if I enter a number as a parameter, it functions correctly, but when I enter a name, nothing happens.


Code:
#!/bin/bash

name=$1
number=$2

if [ $# -eq 0 ]; then
        echo "Two arguments are expected in the form of ./scriptname [name number]"
fi


case $name in
        $1)

                if [[ $1 == [[:alpha]]* ]]; then
                        if grep -qiw "$name" teledir.txt; then
                                echo "$name exists"
                        else
                                echo "Name  does NOT exist"
                        fi


                elif [[ $1 == [0-9]* ]]; then
                        if grep -qiw "$name" teledir.txt; then
                                echo "$name  exists"
                       else
                                echo "Number does NOT exist"
                       fi
                fi


esac

# 7  
This is how I would approach the problem shown in post #1, making use of bash features like "parameter expansion / Remove matching suffix pattern" and testing empty "conditional expressions". It could seriously benefit from some polishing, e.g. combining grep runs, variable quoting, error handling, and upfront argument compliance checks. Try
Code:
name=$1
number=$2
FN=teledir.txt

case  $# in
        1)      if [ ${name%%[[:digit:]]*} ]
                  then  if ! grep -iw "$name:" $FN
                          then  echo "Name doesn't exist."
                        fi
                  elif [ ${name%%[[:alpha:]]*} ]
                    then if ! grep -iw "$name" $FN
                           then echo "$name doesn't exist."
                         fi
                  fi ;;
        2)      grep -qi "$name: $number" $FN &&
                  echo "$name: $number exist" ||
                  echo "$name: $number" >> $FN
                ;;
        *)      echo "Two arguments are expected in the form of ./scriptname [name] [number]";;
esac

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