bad substitution problem (bash)

[UBB2]

Hello,

I've started writing bash-scripts, at the moment I try to write a part in which a first digit of a number is checked for containing correct values.
I did this

dummy=${value:0:1}
if [ -z ${dummy##*[^0-6]*} ]; then
invalid=1
fi

to check if the first digit of an entry is between 0-6. It works fine this way. My question is how it is possible to integrate the ${value:0:1} into the if clause so I don't need the dummy variable anymore. I've tried several times, but I always receive an "bad substitution" error. This should be possible, shouldn't it?

Thanks a lot for any help!

== Solution found ==

OK, I finally found out myself...

it can be done via

if [ `expr match "$value '[0-6]*'` = 0 ]

since match checks by default the first digit.

[Sangal-Arun]

Though using expr match is an efficient way....

[/E*Fare/Users/qabuild/aksutil/pumba] $ a=1-JholaLinux

[/E*Fare/Users/qabuild/aksutil/pumba] $ b=JholaLinux-5

[/E*Fare/Users/qabuild/aksutil/pumba] $ c=7JholaLinux

[/E*Fare/Users/qabuild/aksutil/pumba] $ d=JholaLinux-9

[/E*Fare/Users/qabuild/aksutil/pumba] $ echo $a - $b - $c - $d
1-JholaLinux - JholaLinux-5 - 7JholaLinux - JholaLinux-9

[/E*Fare/Users/qabuild/aksutil/pumba] $ if [ `echo ${a:0:1}|grep [0-6]` ];then echo "Timon"; else echo "Nahin Pumba"; fi
Timon

[/E*Fare/Users/qabuild/aksutil/pumba] $ if [ `echo ${b:0,1}|grep [0-6]` ];then echo "Timon"; else echo "Nahin Pumba"; fi
Timon

[/E*Fare/Users/qabuild/aksutil/pumba] $ if [ `echo ${c:0:1}|grep [0-6]` ];then echo "Timon"; else echo "Nahin Pumba"; fi
Nahin Pumba

[/E*Fare/Users/qabuild/aksutil/pumba] $ if [ `echo ${d:0,1}|grep [0-6]` ];then echo "Timon"; else echo "Nahin Pumba"; fi
Nahin Pumba

Hello,

I've started writing bash-scripts, at the moment I try to write a part in which a first digit of a number is checked for containing correct values.
I did this

dummy=${value:0:1}
if [ -z ${dummy##*[^0-6]*} ]; then
invalid=1
fi

to check if the first digit of an entry is between 0-6. It works fine this way. My question is how it is possible to integrate the ${value:0:1} into the if clause so I don't need the dummy variable anymore. I've tried several times, but I always receive an "bad substitution" error. This should be possible, shouldn't it?

Thanks a lot for any help!

== Solution found ==

OK, I finally found out myself...

it can be done via

if [ `expr match "$value '[0-6]*'` = 0 ]

since match checks by default the first digit.

[UBB2]

Thanks, I'll keep that in mind, too - I have just recently learned what | is for in such a context