07-12-2010
Use popen...it will give you a pointer to the output of date which can then be manipulated.
10 More Discussions You Might Find Interesting
1. Programming
hi all:
i want to store the current date in to a file from a program.
every time i execute the prg the date should get appended into the file.
help me plz (2 Replies)
Discussion started by: bankpro
2 Replies
2. Shell Programming and Scripting
HI
I am trying to store the output of this awk command
awk -F, {(if NR==2) print $1} test.sr
in a variable when I am trying v= awk -F, {(if NR==2) print $1} test.sr
$v = awk -F, {(if NR==2) print $1} test.sr
but its not working out .
Any suggestions
Thanks
Arif (3 Replies)
Discussion started by: mab_arif16
3 Replies
3. UNIX for Dummies Questions & Answers
Hi unix gurus,
I am trying to store the result of a command into a variable.
But it is not getting stored.
x='hello'
y=echo $x | wc -c
but it is giving the output as 0(zero)
Pls help me its very urgent (7 Replies)
Discussion started by: ravi raj kumar
7 Replies
4. Shell Programming and Scripting
Hi all,
Currently, i have a log file seperated by 'tab' and each record starting with a new line. i managed to retrieve the column that i'm interested in. (source_ip_address: xxx.xxx.xxx.xxx).
example of awk output: '{ print $43 }' assuming the field is at column 43.
10.10.10.10... (4 Replies)
Discussion started by: faelric
4 Replies
5. Shell Programming and Scripting
Hello All,
I have coded a C program which looks something like below... (program name: test.c)
#include<stdio.h>
main()
{
int dist,dm,dcm;
printf(" Enter the distance between 2 cities in KM : ");
scanf("%d",&dist);
dm=dist*1000;
dcm=dist*10;
printf("Distance between 2 cities in... (6 Replies)
Discussion started by: smarty86
6 Replies
6. Programming
How can I get around this? when my program reaches the following popen job it halts the program until the ping/netstat/ipconfig/traceroute is completed then resume to the rest of the program...
FILE *in;
extern FILE *popen();
char buff;
char newline;
char nstat;
char nping;
... (5 Replies)
Discussion started by: Jess83
5 Replies
7. Shell Programming and Scripting
Hi,
I am using SunOS
I want to serch my previous command
from unix prompt
(like on AIX we can search by ESC -k)
how to get in SunOs
urgent help require. (10 Replies)
Discussion started by: RahulJoshi
10 Replies
8. Shell Programming and Scripting
Hi all,
I'm trying to implement a linear congruential pseudorandom number generator (<http://en.wikipedia.org/wiki/Linear_congruential_generator>), since $RANDOM and /dev/random aren't standardized. I'm referring to the Shell & Utilities volume of POSIX.1-2008, but I'm running into some odd... (3 Replies)
Discussion started by: PehJota
3 Replies
9. Shell Programming and Scripting
My script below seems to be choking because I need the the output of the find command to be stored as a variable that can then be called by used lower in the script.
#!/bin/bash
cd "/resumes_to_be_completed"
var1=find . -mmin -1 -type f \( -name "*.doc" -o -name "*.docx" \)... (1 Reply)
Discussion started by: binary-ninja
1 Replies
10. Shell Programming and Scripting
Hi,
I want keep/save one command's output in an array and later want to iterate over the array one by one for some processing. instead of doing like below-
for str in `cat /etc/passwd | awk -F: '$3 >100 {print $1}' | uniq`
want to store-
my_array = `cat /etc/passwd | awk -F: '$3 >100 {print... (4 Replies)
Discussion started by: sanzee007
4 Replies
LEARN ABOUT REDHAT
pclose
POPEN(3) Linux Programmer's Manual POPEN(3)
NAME
popen, pclose - process I/O
SYNOPSIS
#include <stdio.h>
FILE *popen(const char *command, const char *type);
int pclose(FILE *stream);
DESCRIPTION
The popen() function opens a process by creating a pipe, forking, and invoking the shell. Since a pipe is by definition unidirectional,
the type argument may specify only reading or writing, not both; the resulting stream is correspondingly read-only or write-only.
The command argument is a pointer to a null-terminated string containing a shell command line. This command is passed to /bin/sh using the
-c flag; interpretation, if any, is performed by the shell. The mode argument is a pointer to a null-terminated string which must be
either `r' for reading or `w' for writing.
The return value from popen() is a normal standard I/O stream in all respects save that it must be closed with pclose() rather than
fclose(). Writing to such a stream writes to the standard input of the command; the command's standard output is the same as that of the
process that called popen(), unless this is altered by the command itself. Conversely, reading from a ``popened'' stream reads the com-
mand's standard output, and the command's standard input is the same as that of the process that called popen.
Note that output popen streams are fully buffered by default.
The pclose function waits for the associated process to terminate and returns the exit status of the command as returned by wait4.
RETURN VALUE
The popen function returns NULL if the fork(2) or pipe(2) calls fail, or if it cannot allocate memory.
The pclose function returns -1 if wait4 returns an error, or some other error is detected.
ERRORS
The popen function does not set errno if memory allocation fails. If the underlying fork() or pipe() fails, errno is set appropriately.
If the mode argument is invalid, and this condition is detected, errno is set to EINVAL.
If pclose() cannot obtain the child status, errno is set to ECHILD.
CONFORMING TO
POSIX.2
BUGS
Since the standard input of a command opened for reading shares its seek offset with the process that called popen(), if the original
process has done a buffered read, the command's input position may not be as expected. Similarly, the output from a command opened for
writing may become intermingled with that of the original process. The latter can be avoided by calling fflush(3) before popen.
Failure to execute the shell is indistinguishable from the shell's failure to execute command, or an immediate exit of the command. The
only hint is an exit status of 127.
HISTORY
A popen() and a pclose() function appeared in Version 7 AT&T UNIX.
SEE ALSO
fork(2), sh(1), pipe(2), wait4(2), fflush(3), fclose(3), fopen(3), stdio(3), system(3)
BSD MANPAGE
1998-05-07 POPEN(3)