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Top Forums Shell Programming and Scripting Sed insert text at first line of empty file Post 302497757 by DC Slick on Friday 18th of February 2011 02:17:58 AM
Old 02-18-2011
I don't want to use echo because I want the first line to be a comment, and the rest to be values that a script reads from. If the user deletes the commented line like they're not supposed to, i want the script not to fail and to replace the line. I want sed to say:
Code:
 sed -i 's/^$/#CUSTOM/' infile

but only to the first line. I don't want #CUSTOM to be all over the place where there's new lines.

my commands go in order: touch infile; sed (add #CUSTOM to beginning of this file). I don't want each iteration of the script to add #CUSTOM to the beginning. ONLY if line one is empty or does not contain #CUSTOM
 

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HTTP_PERSISTENT_HANDLES_IDENT(3)					 1					  HTTP_PERSISTENT_HANDLES_IDENT(3)

http_persistent_handles_ident - Get/set ident of persistent handles

SYNOPSIS
string http_persistent_handles_ident ([string $ident]) DESCRIPTION
Query or define the ident of persistent handles. PARAMETERS
o $ident - the identification string RETURN VALUES
Returns the prior ident as string on success or FALSE on failure. EXAMPLES
Example #1 A http_persistent_handles_ident(3) example <?php echo http_persistent_handles_ident("CUSTOM"), " "; echo http_persistent_handles_ident("MyApp1"), " "; http_get("http://www.example.com/"); print_r(http_persistent_handles_count()); ?> The above example will output: CUSTOM stdClass Object ( [http_request] => Array ( [MyApp1] => Array ( [used] => 0 [free] => 1 ) ) [http_request_datashare] => Array ( [GLOBAL] => Array ( [used] => 1 [free] => 0 ) ) [http_request_pool] => Array ( ) ) SEE ALSO
http_persistent_handles_count(3), http_persistent_handles_clean(3). PHP Documentation Group HTTP_PERSISTENT_HANDLES_IDENT(3)
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