Remove composer error: proc_open(): fork failed - Cannot allocate memory

gistfile1.txt

When running composer commands, sometimes you may see Download exception errors, and also this error message:

```
proc_open(): fork failed - Cannot allocate memory
```

To correct this error, you need to enable swap. You can enable swap by running the following commands:

```
/bin/dd if=/dev/zero of=/swapfile bs=1M count=4096
/sbin/mkswap /var/swapfile
/sbin/swapon /var/swapfile
```

The above stated solution is a temporary solution. To enable swap permanently, you need to do the following:

```
sudo fallocate -l 4G /swapfile      // Create a 4GB swap file
ls -lh /swapfile
sudo chmod 600 /swapfile            // Only root user can read the file
ls -lh /swapfile
sudo mkswap /swapfile               // Setup swap space                     
sudoswapon /swapfile                // Enable swap space
sudo swapon -s                      // Check if swap is enabled
free -m                             // Check if swap is showing in memory

// To make swap permanent
sudo nano /etc/fstab
/swapfile   none    swap    sw    0   0     // Add it at end of line
```