• Find the 25 biggest files into a filesystem:

# find /var -xdev -type f -ls | sort +6nr | head -25 

• Find the zero size files and modified in the 5 latest days:

# find /var -mtime -5 -size 0c -ls

• Remove empty lines:

# sed '/^$/d' 

• Add at the end of lines containing pattern a special character:

# sed '/hdisk/ s/$/;/g' 

• Remove / replace multiple characters, by one:

# echo "abc;;;;123" | tr -s ';' 
abc;123

• Use bc for decimal calcul

# cap=$(echo 500G | sed 's/G/\*1024/' | sed 's/M//')
# echo "scale=1;$cap" | bc
512000

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