The traditional way to avoid ps | grep | cut | sed | awk | tr | ed | head | tail | kitchen | sink is to use a PID file. Store your program's PID ($$ in shell) in a file so other things can track if you're still running or died unexpectedly.
Much less of a kludge and should work on most systems.
Hi Guys,
I need to set the value of $7 to zero in case $7 is NULL. I've tried the below command but doesn't work. Any ideas. thanks guys.
MEM=`ps v $PPID| grep -i db2 | grep -v grep| awk '{ if ( $7 ~ " " ) { print 0 } else { print $7}}' `
Harby. (4 Replies)
Hello,
I looking to use grep to return a string with exactly n matches.
I'm building off this:
ls -aLl /bin | grep '^.\{9\}x' | tr -s ' '
-rwxr-xr-x 1 root root 632816 Nov 25 2008 vi
-rwxr-xr-x 1 root root 632816 Nov 25 2008 view
-rwxr-xr-x 1 root root 16008 May 25 2008... (7 Replies)
Hello,
I'm working on unix with grep (GNU grep) 2.5.1. I'm going through some of the newer regex syntax using Regular Expression Reference - Advanced Syntax a guide.
ls -aLl /bin | grep "\(x\)"
Which works, just highlights 'x' where ever, when ever.
I'm trying to to get (?:) to work but... (4 Replies)
Hi All, I need to grep few files which has words like the below in the file name , which i want to put it in a file and and grep for the files which contain these names and move it to a new directory ,
full file name -C20091210.1000-20091210.1100_SMGBSC3:1000... (2 Replies)
I have a directory I need to grep which consists of numbered sub directories. The sub directory names change daily. A file resides in this main directory that shows which sub directories are FULL backups or INCREMENTAL backups.
My goal is to grep the directory for the word "full" and then... (2 Replies)
The command ps -eaf gives inconsistent result when executed on XYZ server (the command shows 1, 2 or 3 instances of the process. Ideally it should show only 1). I have attached the script file that was executed and the corresponding output. When the same script was executed on ABC server it gave... (1 Reply)
Hello.
I want to get all modules which are loaded and which name are exactly 2 characters long and not more than 2 characters and begin with "nv"
lsmod | (e)grep '^nv????????????
I want to get all modules which are loaded and which name begin with "nv" and are 2 to 7 characters long
... (1 Reply)
Hi,
I have a number of files containing the information below.
"""""
Fundallinfo
6.3950 14.9715 14.0482
"""""
I would like to grep for Fundallinfo and use it to read the next line? I ideally would like to read the three numbers that follow in the next line and... (2 Replies)
Here is my grep string to print only the last occurrence, with before and after lines. Note that the tail Argument is sum of B and A args + 1, so that it prints the data of only the last 1 match. Now I need to print last 2 such matches. I thought of doubling the tail arg like 5+5+1 (For -- line),... (2 Replies)
Discussion started by: samjna
2 Replies
LEARN ABOUT MOJAVE
pidfile
PIDFILE(3) BSD Library Functions Manual PIDFILE(3)NAME
pidfile_open, pidfile_write, pidfile_close, pidfile_remove -- library for PID files handling
LIBRARY
Utility functions from BSD systems (libbsd, -lbsd)
SYNOPSIS
#include <bsd/libutil.h>
struct pidfh *
pidfile_open(const char *path, mode_t mode, pid_t *pidptr);
int
pidfile_write(struct pidfh *pfh);
int
pidfile_close(struct pidfh *pfh);
int
pidfile_remove(struct pidfh *pfh);
DESCRIPTION
The pidfile family of functions allows daemons to handle PID files. It uses flopen(3) to lock a pidfile and detect already running daemons.
The pidfile_open() function opens (or creates) a file specified by the path argument and locks it. If a file can not be locked, a PID of an
already running daemon is returned in the pidptr argument (if it is not NULL). The function does not write process' PID into the file here,
so it can be used before fork()ing and exit with a proper error message when needed. If the path argument is NULL, /var/run/<progname>.pid
file will be used.
The pidfile_write() function writes process' PID into a previously opened file.
The pidfile_close() function closes a pidfile. It should be used after daemon fork()s to start a child process.
The pidfile_remove() function closes and removes a pidfile.
RETURN VALUES
The pidfile_open() function returns a valid pointer to a pidfh structure on success, or NULL if an error occurs. If an error occurs, errno
will be set.
The pidfile_write(), pidfile_close(), and pidfile_remove() functions return the value 0 if successful; otherwise the value -1 is returned and
the global variable errno is set to indicate the error.
EXAMPLES
The following example shows in which order these functions should be used. Note that it is safe to pass NULL to pidfile_write(),
pidfile_remove() and pidfile_close() functions.
struct pidfh *pfh;
pid_t otherpid, childpid;
pfh = pidfile_open("/var/run/daemon.pid", 0600, &otherpid);
if (pfh == NULL) {
if (errno == EEXIST) {
errx(EXIT_FAILURE, "Daemon already running, pid: %jd.",
(intmax_t)otherpid);
}
/* If we cannot create pidfile from other reasons, only warn. */
warn("Cannot open or create pidfile");
}
if (daemon(0, 0) == -1) {
warn("Cannot daemonize");
pidfile_remove(pfh);
exit(EXIT_FAILURE);
}
pidfile_write(pfh);
for (;;) {
/* Do work. */
childpid = fork();
switch (childpid) {
case -1:
syslog(LOG_ERR, "Cannot fork(): %s.", strerror(errno));
break;
case 0:
pidfile_close(pfh);
/* Do child work. */
break;
default:
syslog(LOG_INFO, "Child %jd started.", (intmax_t)childpid);
break;
}
}
pidfile_remove(pfh);
exit(EXIT_SUCCESS);
ERRORS
The pidfile_open() function will fail if:
[EEXIST] Some process already holds the lock on the given pidfile, meaning that a daemon is already running.
[ENAMETOOLONG] Specified pidfile's name is too long.
[EINVAL] Some process already holds the lock on the given pidfile, but PID read from there is invalid.
[EAGAIN] Some process already holds the lock on the given pidfile, but the file is truncated. Most likely, the existing daemon is
writing new PID into the file.
The pidfile_open() function may also fail and set errno for any errors specified for the fstat(2), open(2), and read(2) calls.
The pidfile_write() function will fail if:
[EINVAL] Improper function use. Probably called before pidfile_open().
The pidfile_write() function may also fail and set errno for any errors specified for the fstat(2), ftruncate(2), and write(2) calls.
The pidfile_close() function may fail and set errno for any errors specified for the close(2) and fstat(2) calls.
The pidfile_remove() function will fail if:
[EINVAL] Improper function use. Probably called not from the process which made pidfile_write().
The pidfile_remove() function may also fail and set errno for any errors specified for the close(2), fstat(2), write(2), and unlink(2) system
calls and the flopen(3) library function.
SEE ALSO open(2), daemon(3), flopen(3)AUTHORS
The pidfile functionality is based on ideas from John-Mark Gurney <jmg@FreeBSD.org>.
The code and manual page was written by Pawel Jakub Dawidek <pjd@FreeBSD.org>.
BSD October 20, 2008 BSD