~~NOTOC~~
====== Find  Stuff======
  * looking for **duplicate** filenames in 2 directories
<code>
fdupes --recurse dir1/ dir2/ </code>
  * find a **word** in a file 
<code>
grep -rnw '/path/to/files/' -e "pattern"</code>
  * find all **socket** files your system runs
<code>
find / -type s
</code>
  * find the latest file in a folder/subfolder
<code>
find . -type f -printf '%T@ %P\n' | sort -n | awk '{print $2}'
</code>
  * show files greater than 1G
<code>
du -h * | grep '^\s*[0-9\.]\+G'
</code>
Change 'G' to 'M' for MB output.
====== Differences======
  * between files, showing side by side
<code>
diff -y file1 file2 | less
</code>
  * differences of files between directories
<code>
diff <(ls -a /dir1/) <(ls -a /dir 2/)
</code>
or compare 
<code>
comm <(ls -a /dir/) <(ls -a /dir2/)
</code>
\\
====== Maintenance======
  * kill a process wholesale
<code>
kill $(ps aux | grep "$process_term" | grep -v 'grep' | awk '{print $2}')</code>
  * trim log. example:
<code>
cat /dev/null > modsec_audit.log</code>
See also "log rotate" on mL wiki.
  * remove everything else except...
<code>
rm -rf !(filename)</code>
This works only if extglob is enabled. So
<code>
shopt -s extglob</code>
\\
====== Compression======
  * lossless, multi-thread compression: keeping sourcing file, progress, high efficiency, extrem flag 
<code>
time xz -6ve -k --threads=0 <filename>
</code>
  * compress multiple files
<code>
xz file1.txt file2.txt file3.txt
</code>
  * decompress
<code>
xz -d file.txt.xz
unxz file.txt.xz
</code>
  * test integrity 
<code>
xz -tv <filename>.tar.xz
</code>
  * concatenate multiple files
<code>
xzip -c file1.txt > files.xz
xzip -c file2.txt >> files.xz
</code>
  * concatenate, less, more, grep multiple files
<code>
xzcat test.txt.xz
 test
 example
 text
xzgrep exa test.txt.xz
 example
</code>

====== PHP======
  * View php config
<code>
php -r "print phpinfo();" | grep ".ini"
</code>
or 
<code>
php -i | grep in
</code>
\\
  * reinstall all php packages
<code>
apt-get install --reinstall `dpkg -l | grep 'ii  php7' | awk '{ printf($2" "); next}'`
</code>
====== Log Analysis======
* limiting by date range

sed -n '/8\/Oct\/2019/,/8\/Oct\/2019/ p' access.log