That said, your fix works, thanks so much! Would you mind explaining a tiny snippet?
Is that just prepending c to $0, basically, and if so, why does it need a close, I don't see an open?
Thanks!
Glad it worked. The line you asked about can be confusing.
The variable 'c' is assigned a command and as a result the construct c | getline basically causes awk to execute a popen() call (pipe open) which executes the command in a child process and pipes the results from that command back to awk. The first line of the output from the command is read by the getline, and since no variable is defined, it is parsed into the standard $0, $1... parameters. If a second getline is used with the same command it would attempt to read the next line of input from the command. This would result in and end of file as the date command returns only one line. So, the command must be closed in order for the next to be successful.
Behind the scenes awk maps the command to the file descriptor, so to close the descriptor the command string must be given to the close() function. This is easiest by assigning the command to a variable.
Hope this makes sense.
---------- Post updated at 00:23 ---------- Previous update was at 00:14 ----------
Found a bit more of a description that might do a better job than the paragraph I posted:
Hello Dudes,
I have a task to make a unix shell script that should search for a
specific TEXT in a file.If that TEXT is found, shell script should add
a comment statement before that TEXT line.
Ex : LINE 1 xxxxx
LINE 2 xxxx CALL xxxx
LINE 3 xxxx PERFORM UNTIL
if i... (1 Reply)
hi all,
I am trying to write some message to a file using the following command.
echo "${MESSAGE}" >&1 | tee -a ${File_name}
can the same be done without using echo . I don't want the result to be displayed to the console. Can anyone guide me.
Thanks in advance (6 Replies)
I'm having problems with writing my sql results to a file:
sqlplus -S username/password@DB <<!!
set echo off
set verify off
set showmode off
set feedback off
set timing off
set linesize 250
set wrap off
set pagesize 0
set newpage none
set tab off
set trimspool on
set colsep... (1 Reply)
Hello,
Currently i have a ksh script which will disply the results in plain text format.
I want to format the result in more readable format like Making bold headings and format with colors etc. Something like html or excel format and send that content as email.
Please help me how i can do... (2 Replies)
How can i print the output of a perl script on a unix console and redirect the same in a log file under same directory simultaneously ?
Like in Shell script, we use tee, is there anything in Perl or any other option ? (2 Replies)
Can any one please help, the code works...I want the output of $result to be saved in an output.txt file which is lcoated in c:\\temp\\output.txt.
$filepath="C:\\temp\\ip.txt";
open (HOSTLIST,"$filepath");
@hosts=(<HOSTLIST>);
foreach $host(@hosts)
{
$results = `nslookup... (1 Reply)
Hello Mates
I am trying to write a script, which appends and prepends the text in a file.
I tried testing with a small file and it worked fine.
but for the large file, the script is wiping the entire file and adds only the word to be appended in the file.
mv $file_name $file_name.bak
sed... (6 Replies)
I need to take 2 input files and create 1 output based on matches from each file. I am looking to match field #1 in both files (Userid) and create an output file that will be a combination of fields from
both file1 and file2 if there are any differences in the fields 2,3,4,5,or 6.
Below is an... (5 Replies)
Hi All,
I have written one script in which am writting the result to the log file.
I want to display the results on the console also
if ;
then
echo "$result doesnot match with the host file">>InputHostsFileErrors.txt
else
echo "$result input matches with the host... (7 Replies)
I am writing a shell script with 2 run time arguments. During the execution if i got any error, then it needs to redirected to a error file and in console. Also both error and output to be redirected to a log file. But i am facing the below error.
#! /bin/sh
errExit ()
{
errMsg=`cat... (1 Reply)
Discussion started by: sarathy_a35
1 Replies
LEARN ABOUT MOJAVE
close
close(n) Tcl Built-In Commands close(n)
__________________________________________________________________________________________________________________________________________________NAME
close - Close an open channel
SYNOPSIS
close channelId
_________________________________________________________________DESCRIPTION
Closes the channel given by channelId.
ChannelId must be an identifier for an open channel such as a Tcl standard channel (stdin, stdout, or stderr), the return value from an
invocation of open or socket, or the result of a channel creation command provided by a Tcl extension.
All buffered output is flushed to the channel's output device, any buffered input is discarded, the underlying file or device is closed,
and channelId becomes unavailable for use.
If the channel is blocking, the command does not return until all output is flushed. If the channel is nonblocking and there is unflushed
output, the channel remains open and the command returns immediately; output will be flushed in the background and the channel will be
closed when all the flushing is complete.
If channelId is a blocking channel for a command pipeline then close waits for the child processes to complete.
If the channel is shared between interpreters, then close makes channelId unavailable in the invoking interpreter but has no other effect
until all of the sharing interpreters have closed the channel. When the last interpreter in which the channel is registered invokes close,
the cleanup actions described above occur. See the interp command for a description of channel sharing.
Channels are automatically closed when an interpreter is destroyed and when the process exits. Channels are switched to blocking mode, to
ensure that all output is correctly flushed before the process exits.
The command returns an empty string, and may generate an error if an error occurs while flushing output. If a command in a command pipe-
line created with open returns an error, close generates an error (similar to the exec command.)
EXAMPLE
This illustrates how you can use Tcl to ensure that files get closed even when errors happen by combining catch, close and return:
proc withOpenFile {filename channelVar script} {
upvar 1 $channelVar chan
set chan [open $filename]
catch {
uplevel 1 $script
} result options
close $chan
return -options $options $result
}
SEE ALSO
file(n), open(n), socket(n), eof(n), Tcl_StandardChannels(3)KEYWORDS
blocking, channel, close, nonblocking
Tcl 7.5 close(n)