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vnix27
Asked: 2011-03-10 04:45:13 +0800 CST

What is wrong with following bash script?

  • 772

I wrote following line in my script , but it not assigning any value to variable a

a= grep -n mark /etc/samba/smb.conf |cut -d: f1

I aspect line number where mark string present in smb.conf in variable a. But value of variable is null. What may be the issue

linux scripting bash

5 Answers

  1. Best Answer

    Two things:

    1. There can be no spaces between name of the variable, the = signal and the value of the variable

    2. If you want to put the results of a command or series of commands on a variable, you must enclose it on $(command) or old style backticks. Both lines below are correct and do the same thing: 

      a=`commands`
a=$(commands)

    So your line must be

    a=$(grep -n mark /etc/samba/smb.conf |cut -d: f1)

    There are some differences on how to concatenate the use of backticks or new style $(), check this question on SO to see a good response.

    • 10 
  2. a=`grep -n mark /etc/samba/smb.conf |cut -d: -f1`
    • 2

  3. Try this instead

    a=$(grep -n mark /etc/samba/smb.conf |cut -d: f1)

    Or instead of the $() you could use backticks (which here turn on the nice code look)

    • 2

  4. Should be a=$( ... ) or

    a=` … `
    • 1

  5. Maybe by trying to use cut like this:

    a=`grep -n mark /etc/samba/smb.conf |cut -d: -f1`
    • 1