My "Bread and Butter" Process Keep Alive Perl Script....

Login or Register for Dates, Times and to Reply

Thread Tools Search this Thread
# 1  
My "Bread and Butter" Process Keep Alive Perl Script....

For the newbies, I should have posted this years ago....

Here is the standard (tiny) "bread and butter" perl script (on Linux) I use in my crontab files to insure key processes are alive ( just in case ! ) like httpd, named, sshd, etc.

The example below if for named......


open(PS,"/bin/ps x|") || die "Can't Open PS";
while(<PS>) {
if (/usr\/sbin\/named/) { close PS; exit;}
close PS;

One of my biggest "server fears" is that named will die for some strange reason, so I feel safe knowing that named is always running with the script above.

New Linux/UNIX users might find it useful.
# 2  
Now the haute cuisine:
a shell daemon that polls /proc every 30 seconds:

# name of the daemon to watch

# this script
# e.g.

export PATH=/bin:/usr/bin:/usr/sbin:/sbin

# sh sends SIGHUP on exit, we need to continue
trap 'echo "SIGHUP captured"' HUP

# no interactions, log all output and errors
mkdir -p /var/log
exec </dev/null >/var/log/${me%.*}.log 2>&1

# Solaris needs -z option
zopt=`{ zonename; } 2>/dev/null`
zopt=${zopt:+"-z $zopt"}

echo "$me started with pid $$"
sleep 3
# initiate the pid variables
pid=`pgrep $zopt -x $pname`
[ -n "$pid" ] || exec echo "no $pname process - exiting"
echo "$me watching $pname[$pid]"

# endless loop
while :
 sleep 30
 if [ \! -d /proc/$pid ]; then
  echo "`date` $me $pid is gone!"
  sleep 1
  echo "starting $pname"
  eval $pstart
  sleep 3
  # renew the pid variables
  pid=`pgrep $zopt -x $pname`
  [ -n "$pid" ] || exec echo "no $pname process - exiting"
  echo "$me watching $pname[$pid]"

The script should be background-started (with &) in the start section of the process (here: named) init script, *after* the process is started.
And killed in the stop section of the process start script, *before* the process is killed.

Last edited by MadeInGermany; 01-13-2014 at 03:46 PM..
Login or Register for Dates, Times and to Reply

Previous Thread | Next Thread
Thread Tools Search this Thread
Search this Thread:
Advanced Search

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Bash script - Print an ascii file using specific font "Latin Modern Mono 12" "regular" "9"

Hello. System : opensuse leap 42.3 I have a bash script that build a text file. I would like the last command doing : print_cmd -o page-left=43 -o page-right=22 -o page-top=28 -o page-bottom=43 -o font=LatinModernMono12:regular:9 some_file.txt where : print_cmd ::= some printing... (1 Reply)
Discussion started by: jcdole
1 Replies

2. Shell Programming and Scripting

awk command to replace ";" with "|" and ""|" at diferent places in line of file

Hi, I have line in input file as below: 3G_CENTRAL;INDONESIA_(M)_TELKOMSEL;SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL My expected output for line in the file must be : "1-Radon1-cMOC_deg"|"LDIndex"|"3G_CENTRAL|INDONESIA_(M)_TELKOMSEL"|LAST|"SPECIAL_WORLD_GRP_7_FA_2_TELKOMSEL" Can someone... (7 Replies)
Discussion started by: shis100
7 Replies

3. Shell Programming and Scripting

Send "perl -e '...' " command through SSH, from a perl script

Hey guys I am trying to send a perl -e command to a number of systems using SSH. The command should retrieve some information for me. The problem is, the remote shell tries to interpolate my variables and doesn't get it should take the command literally and just execute it. Below the code.... (2 Replies)
Discussion started by: clrg
2 Replies

4. Shell Programming and Scripting

Ksh script function, how to "EXIT 2" without killing the current process?

Hi, Using AIX 5.3 and Ksh. />ls -al /usr/bin/ksh -r-xr-xr-x 5 bin bin 237420 Apr 10 2007 /usr/bin/ksh /> I recently started working for a new employer. I have written UNIX K-Shell scripts for many years and have never had this particular issue before. Its perplexing me. I have... (2 Replies)
Discussion started by: troym72
2 Replies

5. Red Hat

"service" , "process" and " daemon" ?

Friends , Anybody plz tell me what is the basic difference between "service" , "process" and " daemon" ? Waiting for kind reply .. .. (1 Reply)
Discussion started by: shipon_97
1 Replies

6. Shell Programming and Scripting

Shell script process remains after "exit 1"

I have a script that performs an oracle export: <snip> if then exp / full=y file=${exp_file} log=${exp_log} direct=y feedback=1000000 STATISTICS=NONE buffer=20000000 else exp / full=n owner=${schema_name} file=${exp_file} log=${exp_log} direct=y feedback=1000000... (4 Replies)
Discussion started by: Squeakygoose
4 Replies

7. Shell Programming and Scripting

Startup Script "run process with Timer"

Hi I have a script that execute every X minute for checking new files in a folder and converting to pdf. Is there any way to start this script automatically on linux startup?. I use sleep function in script with infinite loop. while do killall -u `whoami` -q soffice soffice... (0 Replies)
Discussion started by: zawmn83
0 Replies

8. Shell Programming and Scripting

How to include RETURN KEY with Background process "&" in Shell Script

Hello All, I am a newbie in Shell script programming, and maybe you can help me with my query. I need to write a shell script (mntServer.ksh) that will start a background process and also to be able to run another script. The mntServer.ksh script contains: #!/bin/ksh... (1 Reply)
Discussion started by: racbern
1 Replies

9. UNIX for Dummies Questions & Answers

Explain the line "mn_code=`env|grep ""|awk -F"=" '{print $2}'`"

Hi Friends, Can any of you explain me about the below line of code? mn_code=`env|grep ""|awk -F"=" '{print $2}'` Im not able to understand, what exactly it is doing :confused: Any help would be useful for me. Lokesha (4 Replies)
Discussion started by: Lokesha
4 Replies

10. Shell Programming and Scripting

Pid still alive after "control C"

hi , i'm running 2 similar script (ksh) under AIX , the first go normally out when i type "control c" : ps before : notes01 19882 38990 0 11:54:48 pts/0 0:00 recover -s cla0bkpe -d /base/base01 -t May 05 23:02:17 2005 -v -f -a /base/base01/mail/mail-01/xxxx.nsf notes01 30866 40880 0... (4 Replies)
Discussion started by: Nicol
4 Replies

Featured Tech Videos