LinuxQuestions.org - BASH : how to act based on test against a range of numbers

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hollywoodb

07-05-2006 06:44 PM

BASH : how to act based on test against a range of numbers

alright, I can set a file or a variable with a range of numbers...

for example: (either way is fine by me)

Code:

$ cat range.txt

63

88

99



$ echo $RANGE

63 88 99

I have a test number

Code:

$ echo $TEST

77

I want to run a command when the first number in $RANGE is greater than $TEST, and then stop the test on $RANGE. I DO NOT want the command to run on any number in $RANGE other than the first number greater than $TEST.

for example, (using static numbers for example, and keeping in mind that $TEST is 77 in this example)

Quote:

63 > $TEST (false, do nothing)
88 > $TEST (true, run command)
99 > $TEST (true, do nothing, since first correct conditional already meant and command already run)

Quote:

63 > $TEST (false, do nothing)
88 > $TEST (true, run command, and stop testing $RANGE vs $TEST)

unSpawn

07-05-2006 07:13 PM

Code:

test="77"; range=($(cat range.txt)); for i in $(seq 0 $[${#range[@]}-1]); do

 [ "${range[$i]}" -gt "$test" ] && ( echo "running command"; break ) ; done

spirit receiver

07-06-2006 03:51 AM

Code:

(while read && [[ $REPLY -lt $(( $test + 1 )) ]]; do true; done; echo "\"$REPLY\" is the first number greater than $test or the last line." ) < range.txt

Edit: It seems like the brackets around 'echo "running command"; break' are causing trouble in unSpawn's suggestion (because they are forking a subshell)? See

Code:

while true; do (break); done

But the following works as desired:

Code:

test="77"; range=($(cat range.txt)); for i in $(seq 0 $[${#range[@]}-1]); do

 [ "${range[$i]}" -gt "$test" ] && echo "running command" && break; done

unSpawn

07-06-2006 05:10 AM

Thanks for cleaning up again spirit receiver. I would prefer this below over "&&" since I'm not interested if echo fails or not, but that would be even less then trivial:

Code:

[ "${range[$i]}" -gt "$test" ] && { echo "running command"; break; }; done

spirit receiver

07-06-2006 06:09 PM

Quote:

Originally Posted by unSpawn

I'm not interested if echo fails or not

You're right, even if "echo" is not likely to fail, it seems reasonable to use your syntax in a situation where "echo" is replaced with a command that might fail.

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