Expected result not return in shell script

Question

I wrote the following code in shell script:

#!/bin/bash
tput clear
a=$(date +"%k")
if [ $a -lt 12 ]
then
echo "Hi!Good Morning"
fi
if [ $a -ge 12 -a $a -le 17 ]
then
echo "Hi!Good Afternoon"
fi
if [ $a -gt 17 -a $a -le 19 ]
then
echo "Hi!Good Evening"
fi
if [ $a -gt 19 -a $a -le 24 ]
then
echo "Hi!Good Night"
fi
while [ : ]
do

    echo "BCSE!!\c" 
    read comm
    set comm
    case "$1" in
        [""])
            continue
        ;;
    esac
    case "$1" in
        ["editme"])
            xdg-open "$2"& 
        ;;
    esac
        case "$1" in
        ["newd"])
            mkdir -p "$2"
        ;;
    esac
    case "$1" in
        ["mycontent"])
            if [ -f "$2" ]
            then
                xdg-open "$2"&
            else
                echo "File doesn't exist"
            fi
        ;;
    esac
    case "$1" in
        ["exitbcse"])
                break
        ;;
    esac
    case "$1" in
        [*])
            echo "Wrong command!!";;
    esac
done

The output should be :

Hi!Good morning
BCSE!!editme filename

now the file doesn't open instead I get

Hi!Good morning
BCSE!!editme filename
BCSE!!

Fernando · Accepted Answer · 2014-02-12 03:35:13Z

1

Instead of:

while [ : ]

You may want to write:

while :

or

while true

while [ : ] may work, but not for the right cause, that sentence runs the command [, the command [ checks the expression you wrote inside, as it is a non-empty string it returns a true value (a zero), to ilustrate this, if you run while [ false ] you will also get an infinite loop.

And in the case control structures the options must be written without [] and "". case "$1" in exitbcse) break ;; esac

Edit:

Check this example with the corrections I described above and also other fixes:

#!/bin/bash
tput clear
a=$(date +"%k")
if [ $a -lt 12 ]
then
    echo "Hi!Good Morning"
elif [ $a -ge 12 -a $a -le 17 ]
then
    echo "Hi!Good Afternoon"
elif [ $a -gt 17 -a $a -le 19 ]
then
    echo "Hi!Good Evening"
elif [ $a -gt 19 -a $a -le 24 ]
then
    echo "Hi!Good Night"
fi
while true
do
    echo "BCSE!!\c" 
    read comm option
    case "$comm" in
        "")
            continue
            ;;
        "editme")
            xdg-open "$option"& 
            ;;
        "newd")
            mkdir -p "$option"
            ;;
        "mycontent")
            if [ -f "$option" ]
            then
                xdg-open "$option"&
            else
                echo "File doesn't exist"
            fi
            ;;
        "exitbcse")
            break
            ;;
        *)
            echo "Wrong command!!";;
    esac
done

edited Feb 12, 2014 at 3:35

answered Feb 12, 2014 at 2:43

Fernando

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5 Comments

Paku Over a year ago

!Thanks!!But it gives output wrong command everytime.If i remove case $1 in *) then it goes on give the same output.Why does the other cases not execute?

Fernando Over a year ago

$1 is the first argument you pass to the script, if you want to use the value you have read from keyboard use case "$comm", also the command set in this script has no effect, you can skip it.

Paku Over a year ago

Yes it works for exitbcse case.But the other cases do not work.I have changed $1 to $comm

Fernando Over a year ago

Check the last edit I did, in the last if in order to check if a file exists you must use the [ command (yes it is a command, you can call it test if you want, for example if test -f "$option").

Paku Over a year ago

@Fernado -Yes i know file check and yeah your code helped me to finish it.It worked!

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