How to negate Bash's Regular Expression Matching Operator

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Bash has the =~ regular expression matching operator. Here is an example of using it:

#!/bin/bash

input=$1


if [[ "$input" =~ "[0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]" ]]
# ^ NOTE: Quoting not necessary, as of version 3.2 of Bash.
# NNN-NN-NNNN (where each N is a digit).
then
 echo "Social Security number."
 # Process SSN.
else
 echo "Not a Social Security number!"
 # Or, ask for corrected input.
fi

For negation, all the examples I have seen rely on an else clause. For situations where I am only interested in negative matches, is there a better way that making a non-functional if clause?

For example, if I only cared about the case where the above input is not a Not a Social Security number, what is the right way to go about this?

asked 3 mins ago

MountainX

4,7732469122

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up vote
0
down vote

favorite

Bash has the =~ regular expression matching operator. Here is an example of using it:

#!/bin/bash

input=$1


if [[ "$input" =~ "[0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]" ]]
# ^ NOTE: Quoting not necessary, as of version 3.2 of Bash.
# NNN-NN-NNNN (where each N is a digit).
then
 echo "Social Security number."
 # Process SSN.
else
 echo "Not a Social Security number!"
 # Or, ask for corrected input.
fi

For negation, all the examples I have seen rely on an else clause. For situations where I am only interested in negative matches, is there a better way that making a non-functional if clause?

For example, if I only cared about the case where the above input is not a Not a Social Security number, what is the right way to go about this?

asked 3 mins ago

MountainX

4,7732469122

add a commentÂ |Â

up vote
0
down vote

favorite

Bash has the =~ regular expression matching operator. Here is an example of using it:

#!/bin/bash

input=$1


if [[ "$input" =~ "[0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]" ]]
# ^ NOTE: Quoting not necessary, as of version 3.2 of Bash.
# NNN-NN-NNNN (where each N is a digit).
then
 echo "Social Security number."
 # Process SSN.
else
 echo "Not a Social Security number!"
 # Or, ask for corrected input.
fi

For negation, all the examples I have seen rely on an else clause. For situations where I am only interested in negative matches, is there a better way that making a non-functional if clause?

For example, if I only cared about the case where the above input is not a Not a Social Security number, what is the right way to go about this?

asked 3 mins ago

MountainX

4,7732469122

Bash has the =~ regular expression matching operator. Here is an example of using it:

#!/bin/bash

input=$1


if [[ "$input" =~ "[0-9][0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]" ]]
# ^ NOTE: Quoting not necessary, as of version 3.2 of Bash.
# NNN-NN-NNNN (where each N is a digit).
then
 echo "Social Security number."
 # Process SSN.
else
 echo "Not a Social Security number!"
 # Or, ask for corrected input.
fi

For negation, all the examples I have seen rely on an else clause. For situations where I am only interested in negative matches, is there a better way that making a non-functional if clause?

For example, if I only cared about the case where the above input is not a Not a Social Security number, what is the right way to go about this?

bash regular-expression pattern-matching

asked 3 mins ago

MountainX

4,7732469122

asked 3 mins ago

MountainX

4,7732469122

asked 3 mins ago

MountainX

4,7732469122

asked 3 mins ago

MountainX

4,7732469122

asked 3 mins ago

MountainX

4,7732469122

add a commentÂ |Â

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