Quoting multiple types of quotes

Question

Hi I have the following file:

$ cat file.txt
col1    col2    col3
zz2 mm  uu
pp3 yy  kk
ss2 tt  ll
zz3 mm  uu
pp23    yy  kk
ss3 tt  ll
ss3 aa  44
33c 22  99

I want to sort it using awk with the following unix command. This command sorts the tab file first on column1 and then on column2.

$ awk 'NR==1; NR > 1 {print $0 | "sort -t\"\t\" -k1 -k2"}' file.txt

and it works perfect.

$ awk 'NR==1; NR > 1 {print $0 | "sort -t\"\t\" -k1 -k2"}' file.txt
col1    col2    col3
33c 22  99
pp23    yy  kk
pp3 yy  kk
ss2 tt  ll
ss3 aa  44
ss3 tt  ll
zz2 mm  uu
zz3 mm  uu

My problem starts when I want to call it using Php as bash argument.

My code works fine if I call

print(shell_exec(/bin/bash -c "ls -l")) 

Now I want to do the same for sorting command. Below is my php code:

$inpfile= 'file.txt';
$outfile= 'fileout.txt';
$bash = '/bin/bash ';
print(shell_exec($bash. " -c  \"ls -l\"")); print"<br />";

$command = 'awk \'NR==1; NR > 1 {print $0 | "sort -t\"\t\" -k1 -k2" }\' '.$inpfile . " > " . $outfile; 
print("<br>". $command); //awk 'NR==1; NR > 1 {print $0 | "sort -t\"\t\" -k1 -k2" }' file.txt > fileout.txt

shell_exec($bash. " -c \"$command\""); //Gives error because of improper quotes. 
/*
$escaped = escapeshellarg($command);
$command1 = $bash. ' -c '.$escaped ; 
print("<br>". $command1);
//shell_exec($command1); 
*/

Help appreciated. Thanks

Answer 1

You don't need to use /bin/bash while using shell_exec function. You whole code can be cleaned up like this (and it works fine):

<?php
$inpfile= 'file.txt';
$outfile= 'fileout.txt';
$command = 'awk \'NR==1; NR > 1 {print $0 | "sort -t\"\t\" -k1 -k2" }\' '
           . $inpfile . ' > ' . $outfile; 
var_dump($command);
shell_exec("$command"); // now works fine without any error
?>