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bash shellscript for loop two variables with input from two files

I have a file1:

I need to compare usedmem(column5)from file2 with free memory(column4) from file1. If free memory(column4) from file1 is greater than usedmem(column5)from file2. The output should be VM(column2) from file2 can be relocated to storage(column1) in file1. Files are sorted in descending order

storage,totalmem,usedmem,freemem 0843,524230,241374,282856 0867,524230,253339,270891 0842,524230,291427,232803 0868,262086,48660,213426 0849,524230,335445,188785 0844,524230,335446,188784 0860,524230,354981,169249 0855,524230,354984,169246 0862,524230,354985,169245 0853,524230,354986,169244 0850,524230,411733,112497 0857,524230,411734,112496 0841,524230,411734,112496 0839,524230,411735,112495 0848,524230,411736,112494 0851,524230,411737,112493

file2

storage, vm ,rack,usedcpu,usedmem,type 0839,x0aaa05,US1 DA12,4,78851,FA 0839,x0aaa01,US1 DA12,5,10243,OIM 0839,x0aaa03,US1 DA12,6,4099,OHS

Desired output -

significant memory does not exist in 0843 to relocate x0aaa06 x0aaa05 can be relocated to 0867 x0aaa01 can be relocated to 0842 x0aaa03 can be relocated to 0868

I have been trying to use for loop to pass something like

for i in `cat file2|wc -l` do j=`cat file1|cut -d, -f4` m=`cat file2|cut -d, -f5` file1_dom=`cat file1|cut -d, -f1` file2_vm=`cat file2|cut -d, -f2` if [[ `${j} -gt ${m}` ]] then echo ${file2_vm} can be reclocated to ${file1_dom} fi done

output - erroring out 

-bash: 282856: command not found

example 2-

set -- $( cat file1|cut -d, -f4 ) for i in `cat file2|cut -d, -f5` do if [[ $1 -gt $i ]] then echo $1 can be relocated to $i fi done

Output - 

282856 can be relocated to 78851 282856 can be relocated to 10243 282856 can be relocated to 4099
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  • please, take a look at the editing help, especially the first point about code block formatting. Then take some time to edit the formatting of your post to make the question more readable. Also, there's no need to use shorthand for words like "output" (which I suppose you mean with "o/p"). The bits are cheap enough to spell it out, and the question is more understandable without uncommon abbreviations. Commented Dec 15, 2018 at 15:06
  • Also please explain (in words) the logic applied to combine both files in order to create the output. Commented Dec 15, 2018 at 15:09
  • I need to compare usedmem(column5)from file2 with free memory(column4) from file1. If free memory(column4) from file1 is greater than usedmem(column5)from file2. The output should be VM(column2) from file2 can be relocated to storage(column1) in file1. Commented Dec 15, 2018 at 15:15
  • formatted code as well and have rewritten bits as suggested Commented Dec 15, 2018 at 15:16
  • If I understand correctly, ALL freemem entries in file1 are greater than ALL usedmem entries in file2. So - should the output have 16 * 3 = 48 lines reporting all VMs to be relocatable? Commented Dec 15, 2018 at 19:10

1 Answer 1

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for i in `cat file2|wc -l` do j=`cat file1|cut -d, -f4` m=`cat file2|cut -d, -f5` file1_dom=`cat file1|cut -d, -f1` file2_vm=`cat file2|cut -d, -f2` if [[ `${j} -gt ${m}` ]] then echo ${file2_vm} can be reclocated to ${file1_dom} fi done

Several issues I see with your code fragment:

  • Don't use backticks to start sub-shell, they've been deprecated for some time. Prefer the $(cmd) syntax.
  • It's unnecessary to write cat file2 | wc -l for example, wc -l file2 is shorter and more efficient. (No need to start cat, pipe its stdout to wc, etc.)
  • You should always, always, always quote all variable substitutions unless you want them to be subject to word splitting and globbing. I'm referring to unqouted ${file1_dom}. Also, it's unnecessary to write ${file1_dom}, $file1_dom would be preferred (the ${...} syntax offers some other goodies which are unnecessary here).
  • Likewise, you should always prevent common scripting errors by adding -eu to the interpreter line (shebang) of your scripts.
  • You don't need to use [[ for simple numerical comparisons, [ is sufficient.
  • The bug is probably in the comparison: ${j} -gt ${m} is surrounded by backticks and hence executed in a subshell, so that the value of j is taken as command name. (That's where the message comes from.) You want something like if [ "$j" -gt "$m" ]; then ..., applying all of the rules above.

If you choose to rewrite your script in accordance with these rules, please add it to your original post, so that others can benefit from seeing that correct scripting makes difference.

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