Basically I am trying to write a short script to report total space used on /u0? file systems. This is what I was trying to do:
But it returns no output.
This works however:
And can all of this be done in awk (eliminate the grep and sed statements)?
Is there a way to know whether is pipe is opened in read or write mode.I mean is there any signal that is generated when a pipe is opened in read or write mode.
If you have some solution .please let me know ........ (2 Replies)
Hi,
Can any one please help me with this. Am struggling hard to get a solution.
I am doing telnet through a C program and getting the stdout file descriptor of the remote machine to pipe.
read() function is getting data, But whenl it receives SOH character ie. ^A ( Start of heading = Console... (2 Replies)
Could anyone tell me whats wrong whit this piping? the commands that they execute are correct. the command I am trying is ls|wc. Both processes go to the right if statement.
for(i=0;i<argc;i++){
if(i==0&&argc>1){//first command
if(pipe(pipa1)==-1)
... (2 Replies)
Hello !
I want to process a text file in order to extract desired data using sed and grep... Now I am facing a problem piping to grep... nothing happens..
The text consists of blocks of 3 lines that may (or not) contain the Desired data.
the desired data is on each 2... (4 Replies)
Is there a way I can do this:
search for text and replace line containing matched text with a different line?
For example:
"I want to replace text"
I want to search for replace and then change the line to
I am perplexed.
Hope that makes sense.
Thanks in advance. (4 Replies)
hi i am having issues with extra pipe.
i have a data file and i need to remove the extra pipe in the(example 4th and 7thline) in datafile. there are many other line and filed like this which i need to remove from files. The sample data is below:
270 31|455004|24/03/2010|0001235|72
271... (3 Replies)
Hi all,
Im trying to do a simple program which ask the user for a unix command with the arguments. The program fork and the two process communicate with pipes. The child process call execvp with the command and the father process read the result of the execvp via the pipe.
This program works... (11 Replies)
Hi,guys:
I want to use c to implement a pipe. For example:
ps auxwww | grep fred | more
I forked three child processes. Each is responsible for each command, and pipe to next one.
for(i=0;i<2;i++)
pipe(fd)
if(child==1) // child 1
{
close(1)
dup2(fd,1)
close(fd)
}... (3 Replies)
<tr><th align=right valign=top>Faulty_Part</th><td align=left valign=top>readhat version 6.0</td></tr> <tr><th align=right valign=top>Submit_Date</th><td align=left valign=top>2011-04-28 02:08:02</td></tr> .......(a long string)
I want to get all the field between "left valign=top>" and "... (2 Replies)
Hi Friends,
I am using a command that prints certain lines from a file.
For ex:
cat input
abc chr1 456
def chr1 789
ghi chr1 999
jjj chr1 777
jhk chr7 914
My command
awk '{if($2=="chr1" && $3>=456 && $3<=999) {print $0}}' OFS="\t" input
Output being printed is
abc chr1 456 (7 Replies)
Discussion started by: jacobs.smith
7 Replies
LEARN ABOUT PLAN9
grep
GREP(1) General Commands Manual GREP(1)NAME
grep - search a file for a pattern
SYNOPSIS
grep [ option ... ] pattern [ file ... ]
DESCRIPTION
Grep searches the input files (standard input default) for lines (with newlines excluded) that match the pattern, a regular expression as
defined in regexp(6). Normally, each line matching the pattern is `selected', and each selected line is copied to the standard output.
The options are
-c Print only a count of matching lines.
-h Do not print file name tags (headers) with output lines.
-i Ignore alphabetic case distinctions. The implementation folds into lower case all letters in the pattern and input before interpre-
tation. Matched lines are printed in their original form.
-l (ell) Print the names of files with selected lines; don't print the lines.
-L Print the names of files with no selected lines; the converse of -l.
-n Mark each printed line with its line number counted in its file.
-s Produce no output, but return status.
-v Reverse: print lines that do not match the pattern.
Output lines are tagged by file name when there is more than one input file. (To force this tagging, include /dev/null as a file name
argument.)
Care should be taken when using the shell metacharacters $*[^|()= and newline in pattern; it is safest to enclose the entire expression in
single quotes '...'.
SOURCE
/sys/src/cmd/grep.c
SEE ALSO ed(1), awk(1), sed(1), sam(1), regexp(6)DIAGNOSTICS
Exit status is null if any lines are selected, or non-null when no lines are selected or an error occurs.
GREP(1)