check_free_mem

It reports the following performance data:
- total, used, free, shared, buffered and cached memory (as an absolute number and in percents)
- total, used and free swap (as an absolute number and in percents)

The w (warning) and c (critical) thresholds refer to the real free memory which is calculated as:
free memory + cached memory

The W (warning) and C (critical) thresholds refer to the free swap.

Usage:
check_free_mem [-v] [-h] [-w MemWarning] [-c MemCritical] [-W SwapWarning] [-C SwapCritical]

Options:
--version|-v)
prints the program version
--help|-h)
prints this help information
-w)
specifies the warning threshold for free+cached memory
-c)
specifies the critical threshold for free+cached memory
-W)
specifies the warning threshold for free swap
-C)
specifies the critical threshold for free swap

Example:

# ./check_free_mem -w 20 -c 10 -W 5 -C 10

OK; Memory: total 996.8MB, used 272.0MB (27.3%), free 724.9MB (72.7%), shared 0B (0.0%), buffers 69.1MB (6.9%), cached 116.3MB (11.7%), free+cached 841.1MB (84.4%); Swap: total 1024.0MB, used 0B (0.0%), free 1024.0MB (100.0%) | 'used memory'=285175808B;;;0;1045245952 'free memory'=760070144B;;;0;1045245952 'shared memory'=0B;;;0;1045245952 'buffers memory'=72458240B;;;0;1045245952 'cached memory'=121917440B;;;0;1045245952 'free+cached memory'=881987584B;209049190;104524595;0;1045245952 'used swap'=0B;107373363;107373363;0;1073733632

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Oct. 31, 2014 What's new in version 0.93
- the path for binary executables is no more hard coded, which makes the script capable to run on virtually any Linux or UNIX system, without the need to edit it.
- the path for binary executables (grep, awk, free) can be overwritten in the parameters section, at the beginning of the script