Assigning the output of a command to a variable

Question

I am new with unix and I am writing a shell script    When I run this line on the command prompt  it prints the total count of the number of processes which matches   ps -ef   awk   siebsvc    s siebsrvr   amp  amp    awk    a     END   print a      example  the output of the above line is 2 in the command prompt    I want to write a shell script in which the output of the above line  2  is assigned to a variable  which will be later be used for comparison in an if statement    I am looking for something like  output   ps -ef   awk   siebsvc    s siebsrvr   amp  amp    awk    a     END   print a     echo  output   But when i run it  it says output could not be found whereas I am expecting 2  Please help

User · Answer

Try   output   ps -ef   awk   siebsvc    s siebsrvr   amp  amp    awk    a     END   print a      echo  output   Wrapping your command in      tells the shell to run that command  instead of attempting to set the command itself to the variable named  output    Note that you could also use backticks  command     I can highly recommend http   tldp org LDP abs html commandsub html to learn more about command substitution   Also  as 1 CR correctly points out in a comment  the extra space between the equals sign and the assignment is causing it to fail  Here is a simple example on my machine of the behavior you are experiencing   jed MBP    foo   ps -ef  head -1  echo  foo UID PID PPID C STIME TTY TIME CMD  jed MBP    foo    ps -ef  head -1  echo  foo -bash  UID  command not found UID PID PPID C STIME TTY TIME CMD

User · Answer

If you want to do it with multiline multiple command s then you can do this   output    bash  lt  lt EOF  multiline multiple command s EOF     Or   output     multiline multiple command s     Example      bin bash output     bash  lt  lt EOF echo first echo second echo third EOF    echo   output    Output   first second third

User · Answer

You can use a   sign like    OUTPUT   expression

[bash] Assigning the output of a command to a variable

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