Some low level debugging tools in linux.

nm : just lists symbols from obj file
-n sort symbols numerically by address
-D shows dynamic symbols only

Symbol type:
If lowercase, the symbol is local;
if uppercase, the symbol is global (external).
A - symbol's value is absolute, will not be changed by further linking.
B - symbol is in the uninitialized data section (known as BSS).
C - symbol is common. Common symbols are uninitialized data.
D - symbol is in the initialized data section.
N - symbol is a debugging symbol.
R - symbol is in a read only data section.
T - symbol is in the text(code) section.
U - symbol is undefined.

objdump : shows details of obj files
-d disassembly
-S mix source code when disassembles
-x display section/program headers
-r display relocation entries
-w more than 80 character wide display

readelf : displays information about contents of ELF format files
-a Equivalent to: -h -l -S -s -r -d -V -A -I
-e Equivalent to: -h -l -S

-h Display the ELF file header
-l Display the program headers
-S Display the section headers

-s Display the symbol table
--dyn-syms Display the dynamic symbol table

-r Display the relocations (if present)
-d Display the dynamic section (if present)

-W more than 80 character wide display

good examples:
# gcc -c -o test test.c
# readelf -esr test > a.txt

# gcc -g -c -o test test.c
# objdump -drS test > b.txt

PHP code cleaning tools.

PHP LOC statistics:
1. wget --no-check-certificate
2. /opt/lampp/bin/php phploc.phar --exclude="lib" --exclude="Resources" /mnt/data/MyWebProject/ > loc.txt

PHP Mess Detector:
1. Download
2. /opt/lampp/bin/php phpmd.phar /mnt/data/MyWebProject/ text codesize --exclude lib,Resources --reportfile code_complexity.txt
[output format: text; available mess detectors: cleancode, codesize, controversial, design, naming, unusedcode]

PHP Code Sniffer (Enforces a coding standard):
1. Download
2. /opt/lampp/bin/php PHP_CodeSniffer-2.0.0RC1/scripts/phpcs --report-file=code_sniff.txt --standard=Generic --extensions=php --ignore=*/lib/*,*/Resources/* /mnt/data/MyWebProject/

PHP Dead Code Detector:
1. wget --no-check-certificate
2. /opt/lampp/bin/php phpdcd.phar --recursive --exclude="lib" --exclude="Resources" /mnt/data/MyWebProject/ > dead_code.txt

PHP Copy Paste Detector
1. wget --no-check-certificate
2. /opt/lampp/bin/php phpcpd.phar --exclude="lib" --exclude="Resources" /mnt/data/MyWebProject/ > copy_paste.txt

While searching files with find, exclude some directories

find . -type f -name '*.php' ! -path "./lib/*" ! -path "./Resources/*" -exec vim -s /root/vimscript.scr "{}" \;

To print colored text in linux terminal

echo "$(tput setaf 1) Hello $(tput setaf 2) World! $(tput sgr0)"
echo -e "\033[31m Hello \033[32m World! \033[0m"

Option -e means "enable interpretation of backslash escapes"