[SOLVED] How to test variables in script?

Batistuta_g_2000 · 03-07-2013, 06:09 AM

Hi,

Is this doing what i think, I need to make a dir or file if it doesn't exist - have written the below but not sure if it is working or overwriting dir each time?

Code:

function setup_dirs {
     [ -d $IMPORTANT_FILES_DIRECTORY ] || mkdir -p $IMPORTANT_FILES_DIRECTORY
     [ -d $BACKUP_FILES_DIRECTORY ] || mkdir -p $BACKUP_FILES_DIRECTORY
     [ -d $RESTORE_FILES_DIRECTORY ] || mkdir -p $RESTORE_FILES_DIRECTORY
     [ -d ~/assignment1/tmp/ ] || mkdir ~/assignment1/tmp/                              
     [ -d ~/assignment1/tmp/backuplist.txt ] || touch ~/assignment1/tmp/backuplist.txt

shivaa · 03-07-2013, 06:52 AM

Test will work if it's passed to asisgnment. Like you can try:
function setup_dirs {

Code:

    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then
         mkdir -p $IMPORTANT_FILES_DIRECTORY
    fi

OR, combine more conditions, as:

Code:

if ([ -d $IMPORTANT_FILES_DIRECTORY ]; [ -d $BACKUP_FILES_DIRECTORY ]; [ -d $RESTORE_FILES_DIRECTORY ]; [ -d ~/assignment1/tmp/ ]; [ -f ~/assignment1/tmp/backuplist.txt ]); then
mkdir $IMPORTANT_FILES_DIRECTORY $BACKUP_FILES_DIRECTORY $RESTORE_FILES_DIRECTORY ~/assignment1/tmp/
touch ~/assignment1/tmp/backuplist.txt
fi

Note: In order to test a file, use -f option. Also once go through manual of test cmd here.

Batistuta_g_2000 · 03-07-2013, 08:03 AM

Quote:

Originally Posted by shivaa

Test will work if it's passed to asisgnment. Like you can try:
function setup_dirs {

Code:

    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then
         mkdir -p $IMPORTANT_FILES_DIRECTORY
    fi

OR, combine more conditions, as:

Code:

if ([ -d $IMPORTANT_FILES_DIRECTORY ]; [ -d $BACKUP_FILES_DIRECTORY ]; [ -d $RESTORE_FILES_DIRECTORY ]; [ -d ~/assignment1/tmp/ ]; [ -f ~/assignment1/tmp/backuplist.txt ]); then
mkdir $IMPORTANT_FILES_DIRECTORY $BACKUP_FILES_DIRECTORY $RESTORE_FILES_DIRECTORY ~/assignment1/tmp/
touch ~/assignment1/tmp/backuplist.txt
fi

Note: In order to test a file, use -f option. Also once go through manual of test cmd here.

Thanks, changed it to below but getting error somewhere, cant figure it out,
does mkdir have to be on next line?

Code:

function setup_dirs {
    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then mkdir -p $IMPORTANT_FILES_DIRECTORY fi
    if [ -d $BACKUP_FILES_DIRECTORY ]; then mkdir -p $BACKUP_FILES_DIRECTORY fi
    if [ -d $RESTORE_FILES_DIRECTORY ]; then mkdir -p $RESTORE_FILES_DIRECTORY fi
    if [ -d ~/assignment1/tmp/ ]; then mkdir ~/assignment1/tmp/ fi
    if [ -f ~/assignment1/tmp/backuplist.txt ]; then touch ~/assignment1/tmp/backuplist.txt fi
}

shivaa · 03-07-2013, 08:09 AM

Use a semicolon before fi. Or try:

Code:

function setup_dirs {
    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then
    mkdir -p $IMPORTANT_FILES_DIRECTORY
    fi
    if [ -d $BACKUP_FILES_DIRECTORY ]; then
    mkdir -p $BACKUP_FILES_DIRECTORY
    fi
    if [ -d $RESTORE_FILES_DIRECTORY ]; then
    mkdir -p $RESTORE_FILES_DIRECTORY
    fi
    if [ -d ~/assignment1/tmp/ ]; then
    mkdir ~/assignment1/tmp/
    fi
    if [ -f ~/assignment1/tmp/backuplist.txt ]; then
    touch ~/assignment1/tmp/backuplist.txt
    fi
}

OR

Code:

function setup_dirs {
    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then mkdir -p $IMPORTANT_FILES_DIRECTORY; fi
    if [ -d $BACKUP_FILES_DIRECTORY ]; then mkdir -p $BACKUP_FILES_DIRECTORY; fi
    if [ -d $RESTORE_FILES_DIRECTORY ]; then mkdir -p $RESTORE_FILES_DIRECTORY; fi
    if [ -d ~/assignment1/tmp/ ]; then mkdir ~/assignment1/tmp; fi
    if [ -f ~/assignment1/tmp/backuplist.txt ]; then touch ~/assignment1/tmp/backuplist.txt; fi
}

Batistuta_g_2000 · 03-07-2013, 08:11 AM

Quote:

Originally Posted by Batistuta_g_2000

Thanks, changed it to below but getting error somewhere, cant figure it out,
does mkdir have to be on next line?

Code:

function setup_dirs {
    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then mkdir -p $IMPORTANT_FILES_DIRECTORY fi
    if [ -d $BACKUP_FILES_DIRECTORY ]; then mkdir -p $BACKUP_FILES_DIRECTORY fi
    if [ -d $RESTORE_FILES_DIRECTORY ]; then mkdir -p $RESTORE_FILES_DIRECTORY fi
    if [ -d ~/assignment1/tmp/ ]; then mkdir ~/assignment1/tmp/ fi
    if [ -f ~/assignment1/tmp/backuplist.txt ]; then touch ~/assignment1/tmp/backuplist.txt fi
}

Think I got it - Thanks

Code:

#!/bin/bash
function setup_dirs {
    if [ ! -d $IMPORTANT_FILES_DIRECTORY ]; then
mkdir -p $IMPORTANT_FILES_DIRECTORY
fi
    if [ ! -d $BACKUP_FILES_DIRECTORY ]; then
mkdir -p $BACKUP_FILES_DIRECTORY
fi
    if [ ! -d $RESTORE_FILES_DIRECTORY ];
then mkdir -p $RESTORE_FILES_DIRECTORY
fi
    if [ ! -d ~/assignment1/tmp/ ];
then mkdir ~/assignment1/tmp/
fi
    if [ ! -f ~/assignment1/tmp/backuplist.txt ]; then
touch ~/assignment1/tmp/backuplist.txt
fi
}
setup_dirs

shivaa · 03-07-2013, 08:15 AM

Also, one important thing to notice that you've defined function incorrectly. Use () after function name while defining it, as:

Code:

function setup_dirs() {
    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then
    mkdir -p $IMPORTANT_FILES_DIRECTORY
    fi
    if [ -d $BACKUP_FILES_DIRECTORY ]; then
    mkdir -p $BACKUP_FILES_DIRECTORY
    fi
    if [ -d $RESTORE_FILES_DIRECTORY ]; then
    mkdir -p $RESTORE_FILES_DIRECTORY
    fi
    if [ -d ~/assignment1/tmp/ ]; then
    mkdir ~/assignment1/tmp/
    fi
    if [ -f ~/assignment1/tmp/backuplist.txt ]; then
    touch ~/assignment1/tmp/backuplist.txt
    fi
}

OR

Code:

function setup_dirs() {
    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then mkdir -p $IMPORTANT_FILES_DIRECTORY; fi
    if [ -d $BACKUP_FILES_DIRECTORY ]; then mkdir -p $BACKUP_FILES_DIRECTORY; fi
    if [ -d $RESTORE_FILES_DIRECTORY ]; then mkdir -p $RESTORE_FILES_DIRECTORY; fi
    if [ -d ~/assignment1/tmp/ ]; then mkdir ~/assignment1/tmp; fi
    if [ -f ~/assignment1/tmp/backuplist.txt ]; then touch ~/assignment1/tmp/backuplist.txt; fi
}

Batistuta_g_2000 · 03-07-2013, 08:32 AM

Quote:

Originally Posted by shivaa

Also, one important thing to notice that you've defined function incorrectly. Use () after function name while defining it, as:

Code:

function setup_dirs() {
    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then
    mkdir -p $IMPORTANT_FILES_DIRECTORY
    fi
    if [ -d $BACKUP_FILES_DIRECTORY ]; then
    mkdir -p $BACKUP_FILES_DIRECTORY
    fi
    if [ -d $RESTORE_FILES_DIRECTORY ]; then
    mkdir -p $RESTORE_FILES_DIRECTORY
    fi
    if [ -d ~/assignment1/tmp/ ]; then
    mkdir ~/assignment1/tmp/
    fi
    if [ -f ~/assignment1/tmp/backuplist.txt ]; then
    touch ~/assignment1/tmp/backuplist.txt
    fi
}

OR

Code:

function setup_dirs() {
    if [ -d $IMPORTANT_FILES_DIRECTORY ]; then mkdir -p $IMPORTANT_FILES_DIRECTORY; fi
    if [ -d $BACKUP_FILES_DIRECTORY ]; then mkdir -p $BACKUP_FILES_DIRECTORY; fi
    if [ -d $RESTORE_FILES_DIRECTORY ]; then mkdir -p $RESTORE_FILES_DIRECTORY; fi
    if [ -d ~/assignment1/tmp/ ]; then mkdir ~/assignment1/tmp; fi
    if [ -f ~/assignment1/tmp/backuplist.txt ]; then touch ~/assignment1/tmp/backuplist.txt; fi
}

Thanks again, why is this though, works without I think, is it just for read-ability?

colucix · 03-07-2013, 08:58 AM

Actually using the option -p you don't really need to check for the existence of the directory: if the directory exists mkdir -p exits silently and the timestamp of the directory is left untouched. If updating the timestamp of the file is not a problem, the same is true for the touch command: it simply updates the timestamp of existing files.

shivaa · 03-07-2013, 08:58 AM

No, it's not just for readability, but part of syntax. Without (), it will remain incomplete and you will not be able to call it.

Code:

function()          # Defining
{                   # Starting function body
Something           # Body of function           
}                   # Closing
function            # Calling function

Batistuta_g_2000 · 03-07-2013, 09:55 AM

Quote:

Originally Posted by colucix

Actually using the option -p you don't really need to check for the existence of the directory: if the directory exists mkdir -p exits silently and the timestamp of the directory is left untouched. If updating the timestamp of the file is not a problem, the same is true for the touch command: it simply updates the timestamp of existing files.

so doing below is essentially pointless - I should just do a:

mkdir -p $BACKUP_FILES_DIRECTORY unless I want to do something else after.

Code:

    if [ ! -d $BACKUP_FILES_DIRECTORY ]; then
           mkdir -p $BACKUP_FILES_DIRECTORY
    fi

Thanks

chrism01 · 03-07-2013, 05:30 PM

Pretty much, unless you want to eg notify someone at that point.

David the H. · 03-09-2013, 08:55 AM

Code:

setup_dirs() {
    mkdir -p "$IMPORTANT_FILES_DIRECTORY" "$BACKUP_FILES_DIRECTORY" \
             "$RESTORE_FILES_DIRECTORY" "$HOME/assignment1/tmp"

    touch "$HOME/assignment1/tmp/backuplist.txt"
}

mkdir can accept multiple files at once, so there's no need to use a loop unless you want to explicitly test for existence first. Which you might still consider doing in some cases, since the external mkdir process would not spawn unless needed.

The recommended, posixly-correct syntax for function definitions is "funcname()" The function keyword is a bash extension, so "function funcname" is also correct, as long as you're using that shell. In any case you should choose one or the other, and not combine them into "function funcname()". While bash will still accept that without complaint, it isn't really correct.

"~" is really there mostly for interactive use. In scripts you should generally use the "$HOME" variable instead.

Finally, don't forget to always quote all of your variable expansions, to avoid possible word-splitting and globbing expansion problems. It's also generally recommended to avoid using all uppercase variable names, to differentiate them from the uppercase built-in environmental variables.

http://mywiki.wooledge.org/Arguments
http://mywiki.wooledge.org/WordSplitting
http://mywiki.wooledge.org/Quotes

Scripting With Style

Batistuta_g_2000 · 03-11-2013, 09:29 AM

Quote:

Originally Posted by David the H.

Code:

setup_dirs() {
    mkdir -p "$IMPORTANT_FILES_DIRECTORY" "$BACKUP_FILES_DIRECTORY" \
             "$RESTORE_FILES_DIRECTORY" "$HOME/assignment1/tmp"

    touch "$HOME/assignment1/tmp/backuplist.txt"
}

mkdir can accept multiple files at once, so there's no need to use a loop unless you want to explicitly test for existence first. Which you might still consider doing in some cases, since the external mkdir process would not spawn unless needed.

The recommended, posixly-correct syntax for function definitions is "funcname()" The function keyword is a bash extension, so "function funcname" is also correct, as long as you're using that shell. In any case you should choose one or the other, and not combine them into "function funcname()". While bash will still accept that without complaint, it isn't really correct.

"~" is really there mostly for interactive use. In scripts you should generally use the "$HOME" variable instead.

Finally, don't forget to always quote all of your variable expansions, to avoid possible word-splitting and globbing expansion problems. It's also generally recommended to avoid using all uppercase variable names, to differentiate them from the uppercase built-in environmental variables.

http://mywiki.wooledge.org/Arguments
http://mywiki.wooledge.org/WordSplitting
http://mywiki.wooledge.org/Quotes

Scripting With Style

Thanks a million - Really great advice.