How much RAM memory on Ubuntu

The easiest way to see all installed, used, free and available RAM memory on your Ubuntu server is using the free command, we use the -h parameter for human readable sizes:

free -h

This outputs for example:

              total        used        free      shared  buff/cache   available
Mem:          7.8Gi       4.9Gi       609Mi       7.0Mi       2.3Gi       2.6Gi
Swap:         2.0Gi       253Mi       1.8Gi

If you only want one of these specific numbers:

# Total memory (ex. 7.8Gi)
free -h | awk '/^Mem:/ {print $2}'

# Used memory (ex. 4.9Gi)
free -h | awk '/^Mem:/ {print $3}'

# Free memory (ex. 609Mi)
free -h | awk '/^Mem:/ {print $4}'

# Shared memory (ex. 7.0Mi)
free -h | awk '/^Mem:/ {print $5}'

# Buffers/cache memory (ex. 2.3Gi)
free -h | awk '/^Mem:/ {print $6}'

# Available memory (ex. 2.6Gi)
free -h | awk '/^Mem:/ {print $7}'