compiling
Checking Missing Symbols
1 2 ldd -r *.so | grep -v "main" | grep missing
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diff
diff two directories
1 2 diff <dir1> <dir2>
processing columns
print the first column, delimited by space
print the second column, delimited by :
1 2 nawk -Fc '{print $1}' test.txt
print the second column, delimited by :
1 2 nawk -F: '{print $2}' test.txt
patching source
Making Patch -- to represent the addition of a new file, diff it against /dev/null.
Apply Patch
Undo Patch
1 2 diff -Naur test.old test.cpp > test.patch
Apply Patch
1 2 patch test.cpp test.patch
Undo Patch
1 2 patch -R test.cpp test.patch
dump mysql database
1 2 mysqldump -uroot dbname > dbtest.sql
Generate Tags for code navigation.
1 2 ctags -R .*
reverse linked list
Reverse Linked list by reversing links for each node or swapping the nodes at each end.
test for even and odd numbers
1 2 if( x%2 == 0) 3 { 4 print "even number" 5 } 6 elsif( x%2 > 0) 7 { 8 print "odd number" 9 }
swap values without temporary variable
The XOR swap algorithm is an inefficient method of swapping two variables. http://en.wikipedia.org/wiki/Xor_swap_algorithm
1 2 void XORSwap(void *x, void *y) 3 { 4 *x ^= *y; 5 *y ^= *x; 6 *x ^= *y; 7 }
check ip in linux
1 2 #!/usr/bin/perl -w 3 my @ifconfig = `/sbin/ifconfig eth0`; 4 for( @ifconfig ) 5 { 6 if( /(\d+\.\d+\.\d+\.\d+)/ ) 7 { 8 print "IP : $1\n"; 9 last; 10 } 11 }
