bash search for a pattern within a string variable
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bash search for a pattern within a string variable
Does anyone know a bash command to check for a pattern match within a string. For example, if I have a string "1 2 3 4 5". I need a function that would return true if I searched for "2 3", but false if I searched for "8 9".
Thanks
PS I tried searching this forum, but the search kept locking up, so sorry if this has been answered already.
There are built-in tests for extended regular expressions (similar to what druuna uses) or Bash patterns:
Code:
#! /bin/bash
VARIABLE="Let's test this string!"
# This is for regular expressions:
if [[ "$VARIABLE" =~ "Let's.*ring" ]]
then
echo "matched"
else
echo "nope"
fi
# And here we have Bash Patterns:
if [[ "$VARIABLE" == L*ing! ]]
then
echo "matched"
else
echo "nope"
fi
kovacsbv@leviticus:~$ cat tmp.sh
#! /bin/bash
VARIABLE="Let's test this string!"
# This is for regular expressions:
if [[ "$VARIABLE" =~ "Let's.*ring" ]]
then
echo "#1 matched"
else
echo "#1 nope"
fi
if [[ "$VARIABLE" =~ Let\'s.*ring ]]
then
echo "#2 matched"
else
echo "#2 nope"
fi
kovacsbv@leviticus:~$ ./tmp.sh
#1 nope
#2 matched
kovacsbv@leviticus:~$
Actually 'case' is much much faster than even simple matching using 'if', and
can even do pattern and glob matching:
Code:
#!/bin/sh
thisString="1 2 3 4 5"
searchString="1 2"
# if you single quote your input, you could do this
# searchString=$1
case $thisString in
# match exact string
"$searchString") echo yep, it matches exactly;;
# match start of string
"$searchString"*) echo yep, it matches at the start ;;
# match end of string
*"$searchString") echo yep, it matches at the end ;;
# searchString can be anywhere in thisString
*"$searchString"*) echo yep, it matches in the middle somewhere ;;
*) echo nope ;;
esac
Actually 'case' is much much faster than even simple matching using 'if', and
can even do pattern and glob matching:
Code:
#!/bin/sh
thisString="1 2 3 4 5"
searchString="1 2"
# if you single quote your input, you could do this
# searchString=$1
case $thisString in
# match exact string
"$searchString") echo yep, it matches exactly;;
# match start of string
"$searchString"*) echo yep, it matches at the start ;;
# match end of string
*"$searchString") echo yep, it matches at the end ;;
# searchString can be anywhere in thisString
*"$searchString"*) echo yep, it matches in the middle somewhere ;;
*) echo nope ;;
esac
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