CODEWITHSUNDEEP
awkgreptcl
Manisha Kuhar
Manisha Kuhar

Reputation: 9

how to search for a value stored in variable from a file using awk/ grep

It might be trivial, but I am facing problem in using awk for simple purpose like printing row in a file using tcl script. I have variable var :

set var manager

sourcefile.txt:

ajay manager account 45000
sunil clerk account 25000
varun manager sales 50000
amit manager account 47000
tarun peon sales 15000
deepak clerk sales 23000
sunil peon sales 13000
satvik director purchase 80000

I want to put command inside tcl script (awk/grep) which use variable var to search for string in source file and then print the 4th column of the line containing the string. I don't want to search for manager directly, but using var . I used:

awk -v pat="$var"  {$2 ~ pat {print $4 }} sorcefile.txt

But it is giving me error saying

awk: 'pat' argument to '-v' not in var=value form

Also inside tcl script:

awk '/manager/ {print $4}' sourcefile.txt

gives error, and

awk {/manager/ {print $4}} sourcefile.txt

works well So, the required output:

45000
50000
47000

The command I need to put it inside a file, and then execute the file.

Upvotes: 0

Views: 985

Answers (2)

glenn jackman
glenn jackman

Reputation: 247250

It's the position of the quotes.

$ tclsh
% set var manager
manager
+% exec awk -v pat="$var" {$2 ~ pat {print $4}} sourcefile.txt

No output. Let's ask the shell to echo the awk command instead of executing it:

% exec echo awk -v pat="$var" {$2 == pat {print $4}} sourcefile.txt
awk -v pat="manager" $2 == pat {print $4} sourcefile.txt

Note how the double quotes are part of the pattern there?

Let's move the double quotes a bit:

% exec echo awk -v "pat=$var" {$2 == pat {print $4}} sourcefile.txt
awk -v pat=manager $2 == pat {print $4} sourcefile.txt

Note how the quotes are gone? Let's execute it now:

% exec awk -v "pat=$var" {$2 == pat {print $4}} sourcefile.txt
45000
50000
47000

This relates to the Tcl rule for double quotes -- the opening quote must be the first character of a word.

In the first case, the awk pat variable is literally "manager", and as none of the $2 values contains quotes, no matches occur.

Upvotes: 2

Archemar
Archemar

Reputation: 571

this could be simply done in tcl

set var ...
set fi [ open "file.txt" ]
set lines [split [read $fi] "\n"]
close $fi
foreach line $lines {
        set la [ split $line ]
        if { [ lindex $la 1 ] eq $var  } {
                puts [ lindex $la 3 ]
        }

}

note that list index start at 0 and awk's $4' is tcl [lindex $la 3]

Upvotes: 1

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