Get OS error codes

# for i in $(seq 0 181); do perror $i; done 

OS error code   0:  Success

OS error code   1:  Operation not permitted

OS error code   2:  No such file or directory

OS error code   3:  No such process

OS error code   4:  Interrupted system call

OS error code   5:  Input/output error

OS error code   6:  No such device or address

OS error code   7:  Argument list too long

OS error code   8:  Exec format error

OS error code   9:  Bad file descriptor

...

-- vladget

Clear Linux Memory Buffer Cache:

• Free pagecache, dentries and inodes in cache memory # sync; echo 3 > /proc/sys/vm/drop_caches.
• Free dentries and inodes use following command # sync; echo 2 > /proc/sys/vm/drop_caches.
• Free pagecache only use following command # sync; echo 1 > /proc/sys/vm/drop_caches.

-- vladget