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bash if statement

 
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bash if statement
realNoName
post 18 Jun, 2008 - 11:46 PM
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am having problems with my else if statement in bash... it should be going into the elif but it drops down to the else and when it runs its doing something funky

QUOTE
DEBUG-|100|
bash: [: 100: unary operator expected
bash: [100: command not found
DEBUG-else


CODE
echo "DEBUG-|$CURR_STATUS|"    
#server isnt in db
if [ $CURR_STATUS -z ]; then
    echo "DEBUG-in no status set"
    # new server
    CURR_STATUS=100
elif [$CURR_STATUS -eq 100]; then
    echo "DEBUG-in status 100"
else
    echo "DEBUG-else"
fi
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no2pencil
post 19 Jun, 2008 - 01:01 AM
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There are 2 slight syntax errors in your code.

1st, the dash z must come before the variable it's testing on line 4. I don't know why, that's just the way it is.

2nd, you need spaces between your open bracket & close bracket, on line 8.

CODE

echo "DEBUG-|$CURR_STATUS|"
#server isnt in db
if [ -z $CURR_STATUS ]; then
    echo "DEBUG-in no status set"
    # new server
    CURR_STATUS=100
elif [ $CURR_STATUS -eq 100 ]; then
    echo "DEBUG-in status 100"
else
    echo "DEBUG-else"
fi
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realNoName
post 19 Jun, 2008 - 01:36 AM
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sweet thanks no2pencil


p.s. i HATE bash scripting
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Tom9729
post 19 Jun, 2008 - 08:55 PM
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QUOTE
p.s. i HATE bash scripting


I don't mind it, but I use PHP for scripts whenever I can get away with it. smile.gif

This post has been edited by Tom9729: 19 Jun, 2008 - 08:56 PM
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perfectly.insane
post 13 Jul, 2008 - 07:24 AM
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Well, I think the reasoning behind the syntax is easy once one understands the underlying mechanisms here. You see, the [ and ] are not part of the shell language (sometimes they are, but they have to be compatible with older shells). The [ in the if compound statement is really either /bin/[ (a symlink to /bin/test), or is a built in. So, "if [ -z $X ] ; then" should be similar to "if test -z $x ; then". The test binary will ignore the "]" purposely, just to support this functionality. The if statement simply executes whatever comes after it, and evaluates the exit code in order to decide what block to execute thereafter.

BTW, some shells offer a [[ builtin as well, that usually supports a superset of what can be given to the [ external/builtin.
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indrora
post 31 Jul, 2008 - 08:48 AM
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take a look at this (http://sonof.bandit.name/index.php?entry=entry080305-172922#readmore-entry080305-172922 )for a good usage of if's
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