Linux Tips

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Who is SUPER USER in linux

awk -F: '$3 == 0{print $1,"superuser!"}' /etc/passwd
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How to get Environment for a process
If the process id is 920.

(cat /proc/920/environ; echo) : tr "\000" "\n"
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How to list files with their complete path
If 'childdir' is the name of directory.

find childdir -type f -printf "%AY%Am%Ad%AH%AM %p\n" : sort -r : gawk
'{print $2}'
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How to find open files in linux

find /proc -regex "/proc/[0-9]*/fd/.*" -ls
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Formatting man pages

man ls : col -bx > myfile.txt
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Finding the biggest files

ls -l : sort +4n
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Searching files for content

find / -name "filename" : xargs grep -n content
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Largest Directories

du -kx : egrep -v "\./.+/" : sort -n
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List today's files only

ls -al --time-style +%D : grep `date +%D`
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Encrypt some plain text

perl -e 'print crypt("ke", "password");'
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Look for unusual SUID root files

find / -uid 0 -perm -4000 -print
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Look for unusual large files (> 10 Mb)

find / -size +10000k -print
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