03-29-2019
10 More Discussions You Might Find Interesting
1. UNIX for Dummies Questions & Answers
I have been planning to set up a Unix workstation at home to host an Oracle database just for database admin. practice. But I don't know enough about hardware to know whether this can be done on a regular desktop and the required hardware config. If anyone could kindly guide me in this mission I... (4 Replies)
Discussion started by: tmanpakdee
4 Replies
2. UNIX for Advanced & Expert Users
Hi,
I work at IT department of a home furnishing company in Canada. Presently we are working on printer issue on UNIX system and we like to set up a dummy printer on the system. We are not much sure about the procedure to try it and it woul dbe great if we get some advice to go ahead.
Thanks... (3 Replies)
Discussion started by: srabanti
3 Replies
3. Shell Programming and Scripting
Hello guys.
In my script, i have the following code:
echo "The tarfile contains these directorys"
tar -tf file.tar > tarlist.txt
cat tarlist | awk -F/ '{print $1 "/" $2}' | nl
echo "Enter path of the directory you want to extract or just press enter to extract everything: "
read path... (1 Reply)
Discussion started by: noratx
1 Replies
4. Shell Programming and Scripting
I'm not talking about the assembly instruction TAS, a better name could be check-and-set :) Anyway, is there a way to simplify the following
if ; then VAR="something"; fi
I have ~20 variables that should be test-and-set like this, and it really looks lame. (2 Replies)
Discussion started by: rayne
2 Replies
5. Shell Programming and Scripting
Trying to search a log file for a string, starting from a certain point in the log file. I want to return the number of lines that contain the search string and the total number of lines in the log file. Here's the part of the script I'm having problems with:
set -- $(awk -v... (12 Replies)
Discussion started by: mglenney
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6. Solaris
Hi all,
I don't want to enter below command on solaris every time.
How do i permanently set this command on Solaris.
I know that this operation is a piece of cake on redhat because there is a /etc/rc.local file on it.
But Solaris ????
bash-3.00#export PS1="\e (2 Replies)
Discussion started by: getrue
2 Replies
7. UNIX for Dummies Questions & Answers
Howdy, I got a script that adds a esc char before all chars interpeted by bash shell but I wan't other solution. Is there a way to set ' and " as a non quotes type in bash (some local variable)? Have found that scsh is a non-quoting type shell but after reading Why I don't use scsh as a scripting... (3 Replies)
Discussion started by: johny_be_good
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8. Shell Programming and Scripting
I have a bash script using "set -o nounset" to prevent unset variables.
However I have created a trap to run some cleanup options upon exit of the script which works fine for CTRL-C, etc. but if it hits and unset variable the trap does not run and the script bails out without having tidied up... (3 Replies)
Discussion started by: jelloir
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9. Shell Programming and Scripting
Hi,
Will following set up work in bash script? I've got errors if assigning following binary command to a variable. But on the other hand, COMMAND="ls" works. Any explanation please? How can I assign binary command to a variable COMMAND then I can just call ${COMMAND}?
COMMAND="rsync"... (3 Replies)
Discussion started by: hce
3 Replies
10. Shell Programming and Scripting
Hi,
I have 4 parameters passed to my shell and i validate if all four are entered using the following snippet:
if
then echo "Not entered"
else echo "entered"
fi
I get the following output as 'Not entered even when i enter the values for all prompts.
Please advise.
Thanks. (5 Replies)
Discussion started by: Jesshelle David
5 Replies
SHLOCK(1) BSD General Commands Manual SHLOCK(1)
NAME
shlock -- create or verify a lock file for shell scripts
SYNOPSIS
shlock [-du] [-p PID] -f lockfile
DESCRIPTION
The shlock command can create or verify a lock file on behalf of a shell or other script program. When it attempts to create a lock file, if
one already exists, shlock verifies that it is or is not valid. If valid, shlock will exit with a non-zero exit code. If invalid, shlock
will remove the lock file, and create a new one.
shlock uses the link(2) system call to make the final target lock file, which is an atomic operation (i.e. "dot locking", so named for this
mechanism's original use for locking system mailboxes). It puts the process ID ("PID") from the command line into the requested lock file.
shlock verifies that an extant lock file is still valid by using kill(2) with a zero signal to check for the existence of the process that
holds the lock.
The -d option causes shlock to be verbose about what it is doing.
The -f argument with lockfile is always required.
The -p option with PID is given when the program is to create a lock file; when absent, shlock will simply check for the validity of the lock
file.
The -u option causes shlock to read and write the PID as a binary pid_t, instead of as ASCII, to be compatible with the locks created by
UUCP.
EXIT STATUS
A zero exit code indicates a valid lock file.
EXAMPLES
BOURNE SHELL
#!/bin/sh
lckfile=/tmp/foo.lock
if shlock -f ${lckfile} -p $$
then
# do what required the lock
rm ${lckfile}
else
echo Lock ${lckfile} already held by `cat ${lckfile}`
fi
C SHELL
#!/bin/csh -f
set lckfile=/tmp/foo.lock
shlock -f ${lckfile} -p $$
if ($status == 0) then
# do what required the lock
rm ${lckfile}
else
echo Lock ${lckfile} already held by `cat ${lckfile}`
endif
The examples assume that the file system where the lock file is to be created is writable by the user, and has space available.
HISTORY
shlock was written for the first Network News Transfer Protocol (NNTP) software distribution, released in March 1986. The algorithm was sug-
gested by Peter Honeyman, from work he did on HoneyDanBer UUCP.
AUTHORS
Erik E. Fair <fair@clock.org>
BUGS
Does not work on NFS or other network file system on different systems because the disparate systems have disjoint PID spaces.
Cannot handle the case where a lock file was not deleted, the process that created it has exited, and the system has created a new process
with the same PID as in the dead lock file. The lock file will appear to be valid even though the process is unrelated to the one that cre-
ated the lock in the first place. Always remove your lock files after you're done.
BSD
June 29, 1997 BSD