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chmod +x <fileName> # add execute permission to that file (.x.x.x)
chmod +r <fileName> # add read permission to a file
chmod +w <fileName> # add write permission to the file
chmod u+x <fileName> #add execute permission to owner of the file
chmod 400 <fileName> # set file only read permission to owner
#chmod-calculator.com
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# 7 -->full 111
# 6 -->read and write 110
# 5 -->read and execute 101
# 4 -->read only 100
# 3 -->write and execute 011
# 2 -->write only 010
# 1 -->execute only 001
# 0 -->none 000
#in the given example below, 'myFile' is given a full permission
chmod 777 myFile