CODEWITHSUNDEEP
linuxshellecho
learner
learner

Reputation: 905

Shell script, saving the command value to a variable

I am trying to print the value of VARI in the same line followed by a comma, so that i can have a csv file of these values, but i m not able to save the value of VARI = 'cat filename | head -1 | cut -d, -f${i}'

i=0
while (( i<130)) ;
do
  if [[ $i -eq 1 ||  $i -eq 9 || $i -eq 12 || $i -eq 23 || $i -eq 25 || $i -eq 29 ]]
  then
    VARI = 'cat filename | head -1 | cut -d, -f${i}'
    echo  "$VARI ,"   
  fi
  let i=$i+1;
done

output expected is 

4,abc,5,8,xyz,9

Please let me know what i am doing wrong, thanks!

Upvotes: 5

Views: 9800

Answers (1)

knittl
knittl

Reputation: 265231

Use backticks (or $() which can be nested), not single quotes:

VARI=`cat filename | head -1 | cut -d, -f${i}` # or:
VARI=$(cat filename | head -1 | cut -d, -f${i})

Make sure to not have spaces between the variable name, the equal sign, and the variable value.

VAR = x # executes program "VAR" with 2 parameters: "=" and "x"
VAR =x  # executes program "VAR" with a single parameter: "=x"
VAR= x  # executes program "x" with environment variable "VAR" set to an empty value
VAR=x   # assigns value "x" to shell variable "VAR"

Resources: 2.10.2 Shell Grammar Rules of the POSIX.1-2017 specification.

Upvotes: 12

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