23 lines
733 B
Bash
23 lines
733 B
Bash
#From: jrmartin@rainey.blueneptune.com (James R. Martin)
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#Newsgroups: comp.unix.shell
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#Subject: Re: testing user input on numeric or character value
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#Date: 26 Nov 1997 01:28:43 GMT
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# isnum returns True if its argument is a valid number,
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# and False (retval=1) if it is any other string.
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# The first pattern requires a digit before the decimal
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# point, and the second after the decimal point.
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# BASH NOTE: make sure you have executed `shopt -s extglob' before
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# trying to use this function, or it will not work
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function isnum # string
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{
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case $1 in
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?([-+])+([0-9])?(.)*([0-9])?([Ee]?([-+])+([0-9])) )
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return 0;;
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?([-+])*([0-9])?(.)+([0-9])?([Ee]?([-+])+([0-9])) )
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return 0;;
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*) return 1;;
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esac
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}
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