LinuxQuestions.org - My If else statement only enters the first one?

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My If else statement only enters the first one?

Code:

#!/bin/bash





echo $1



if [ $1=="A" ];

        

        then echo 0 > Type.txt

else

        

        if [ $1=="B" ];

                then echo 1 > Type.txt

        else

                if [ $1=="C" ];

                        then echo 2 > Type.txt

                else

                        if [ $1=="D" ];

                                

                                then echo 3 > Type.txt

                                        

                        else

                                echo "Fail"

                        fi

                fi

        fi

fi

My code seems to always think the first if statement is true. What is wrong?

If you run the script as 'bash -vx /path/to/script.sh' you can see all variables filled in etc, etc. Also note there's no need for nesting so:

Code:

if [ "$1" = "A" ]; then

        echo 0 > Type.txt

elif [ "$1" = "B" ]; then

        echo 1 > Type.txt

elif [ "$1" = "C" ]; then

        echo 2 > Type.txt

elif [ "$1" = "D" ]; then

        echo 3 > Type.txt

else

        echo "Fail"

fi

should do and you could alternatively use a case statement:

Code:

case "$1" in

A) echo 0 > Type.txt;;

B) echo 1 > Type.txt;;

C) echo 2 > Type.txt;;

D) echo 3 > Type.txt;;

*) echo "Fail";;

esac

Code:

function help() { echo "Bash scripting guides:

http://www.tldp.org/HOWTO/Bash-Prog-Intro-HOWTO.html 

http://www.tldp.org/LDP/Bash-Beginners-Guide/html/index.html 

http://www.gnu.org/software/bash/manual/html_node/index.html

http://www.grymoire.com/Unix/Sh.html

http://www.tldp.org/LDP/abs/html/ 

http://wooledge.org/mywiki/BashFAQ?action=show&redirect=BashFaq 

http://wooledge.org/mywiki/BashPitfalls"; }

Quote:

Originally Posted by hayloiuy (Post 4332385)

My code seems to always think the first if statement is true. What is wrong?

You didn't put spaces around the "=" sign.

It's not some kind of C-like expression, "[" is a command. You can put any other command after it, too.

The "[" command is basically the test command, but it requires the last argument to be "]". Read man test for more info.

http://mywiki.wooledge.org/BashPitfa..._.3D_d_.5D_.5D