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Check if a string starts with certain values and ends with numbers

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# 1  
Old 09-02-2016
Check if a string starts with certain values and ends with numbers
This is very basic. Yet Iam struggling to get the right pattern for my check.
Apologize in advance to ask a very lame question.

I have to validate if a value of the variable starts with "efgh" and followed by 6 numbers.

Var1="efgh234567"

The condition Iam trying to achieve is similar to the below.
Code:
if [[ ${Var1} == "^efgh[0-9][0-9][0-9][0-9][0-9][0-9]$" ]]; then
....

# 2  
Old 09-02-2016
Quote:
Originally Posted by deepakwins
The condition Iam trying to achieve is similar to the below.
Code:
if [[ ${Var1} == "^efgh[0-9][0-9][0-9][0-9][0-9][0-9]$" ]]; then
....

Your code won't work. You are providing a regular expression, but the == operator expects a glob pattern. You could either use the regexp operator (=~) or write your pattern as a glob-pattern:

Code:
[[ $Var1 == efgh[0-9][0-9][0-9][0-9][0-9][0-9] ]];

# 3  
Old 09-02-2016
Thanks for pointing out the obvious Rovf!
Some how, when I tried the above, it taking anything after "efgh". Its working as if its like "efgh*".
Eg: "efghTest" is also working ok with the check.

Perhaps, could you help me with the syntax for reqexp operator?
# 4  
Old 09-02-2016
Sure?

Code:
Var1=efgh123456
[[ $Var1 == efgh[0-9][0-9][0-9][0-9][0-9][0-9] ]] && echo OK || echo NOK
OK
Var1=efghTest
[[ $Var1 == efgh[0-9][0-9][0-9][0-9][0-9][0-9] ]] && echo OK || echo NOK
NOK

# 5  
Old 09-02-2016
Sorry sir, my bad, I had a typo in my statement. It perfectly worked.
Thanks for your time RudiC!

Iam still curious for the RegEx option though. Smilie
# 6  
Old 09-02-2016
Code:
[[ ${Var1} =~ ^efgh[0-9][0-9][0-9][0-9][0-9][0-9]$ ]] && echo OK || echo NOK
OK

or

Code:
[[ ${Var1} =~ ^efgh[0-9]{6}$ ]] && echo OK || echo NOK

# 7  
Old 09-02-2016
Quote:
Originally Posted by deepakwins
Perhaps, could you help me with the syntax for reqexp operator?
From the bash man page:

An additional binary operator, =~, is available, with the same precedence as == and
!=. When it is used, the string to the right of the operator is considered an
extended regular expression and matched accordingly (as in regex(3)). The return
value is 0 if the string matches the pattern, and 1 otherwise. If the regular
expression is syntactically incorrect, the conditional expression's return value is
2. If the shell option nocasematch is enabled, the match is performed without regard
to the case of alphabetic characters. Any part of the pattern may be quoted to force
the quoted portion to be matched as a string.
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