What is a swap file?
<blockquote>
If the computer runs out of RAM, it swaps out a page to swap space. This way it creates an illusion that there is more space in the RAM. 
</blockquote>
The main advantage of swap space is that if your computer runs out of RAM, it can continue operating. (Without swap space enabled, RAM exhaustion means that something will simply fail; usually in that scenario the OS chooses a process to kill in order to free up some memory, but in some (mostly older) OSs the whole OS could crash) 
<pre><code>#!/bin/sh

# size of swapfile in megabytes
swapsize=1024

# does the swap file already exist?
grep -q "swapfile" /etc/fstab

# if not then create it
if [ $? -ne 0 ]; then
 echo 'swapfile not found. Adding swapfile.'
 dd -l ${swapsize}M /swapfile
 chmod 600 /swapfile
 mkswap /swapfile
 swapon /swapfile
 echo '/swapfile none swap defaults 0 0' &gt;&gt; /etc/fstab
else
 echo 'swapfile found. No changes made.'
fi

# output results to terminal
df -h
cat /proc/swaps
cat /proc/meminfo | grep Swap
</code></pre>

**What is a swap file?**


> 
If the computer runs out of RAM, it swaps out a page to swap space. This way it creates an illusion that there is more space in the RAM. 

The main advantage of swap space is that if your computer runs out of RAM, it can continue operating. (Without swap space enabled, RAM exhaustion means that something will simply fail; usually in that scenario the OS chooses a process to kill in order to free up some memory, but in some (mostly older) OSs the whole OS could crash) 

```
#!/bin/sh

# size of swapfile in megabytes
swapsize=1024

# does the swap file already exist?
grep -q "swapfile" /etc/fstab

# if not then create it
if [ $? -ne 0 ]; then
  echo 'swapfile not found. Adding swapfile.'
  dd -l ${swapsize}M /swapfile
  chmod 600 /swapfile
  mkswap /swapfile
  swapon /swapfile
  echo '/swapfile none swap defaults 0 0' >> /etc/fstab
else
  echo 'swapfile found. No changes made.'
fi

# output results to terminal
df -h
cat /proc/swaps
cat /proc/meminfo | grep Swap
```

Adding Swap Space in Linux

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