How much memory is on my linux server? Run the free command
free -g total used free shared buffers cached Mem: 2 1 0 0 0 1 -/+ buffers/cache: 0 1 Swap: 3 0 3Which will tell you memory in Gigs. You can pass other flags, such as, -m or -k, which will give you the number in megs and kilobytes respectively.
The man page is as follows
FREE(1) Linux User's Manual FREE(1)
NAME free - Display amount of free and used memory in the system
SYNOPSIS free [-b | -k | -m | -g] [-o] [-s delay ] [-t] [-V]
DESCRIPTION free displays the total amount of free and used physical and swap memory in the system, as well as the buffers used by the kernel. The shared memory column should be ignored; it is obsolete.
Options The -b switch displays the amount of memory in bytes; the -k switch (set by default) displays it in kilobytes; the -m switch displays it in megabytes; the -g switch displays it in gigabytes.
The -t switch displays a line containing the totals. The -o switch disables the display of a "buffer adjusted" line. If the -o option is not specified, free subtracts buffer memory from the used memory and adds it to the free memory reported. The -s switch activates continuous polling delay seconds apart. You may actually specify any floating point number for delay, usleep(3) is used for microsecond resolu- tion delay times. The -V displays version information.
FILES /proc/meminfo memory information
SEE ALSO ps(1), slabtop(1), vmstat(8), top(1)