echo "hello world"
pwd
ls
cat access.log
tail -n 5 access.log
grep "GET" access.log
grep -c -P '\t' file-with-tabs.txt
grep -l 500 *
ls | grep 'access.log*'
find . -type f -name "access.log*" -exec grep -hP '500' {} \;
find . -type f -name "access.log*" -exec grep -oP '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}' {} \;
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???
cat access.log | sort
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rm -- -*rm 
find . -type f -name "*.doc" -exec rm {} \;
???
find . -type f -name "*.txt" -exec sed -i 's/challenges are difficult//g' {} \;
???
find . -type f -exec basename {} \;