Hi there,
I was trying to add a line of text in the middle line of a file.
I have counted the lines in the file, and then I divide it into 2, after that I am stuck on how am I suppose to append the line on that file? When I tried to use this command 'second line >> filename' it appends it at... (3 Replies)
Hi all,
I have set up a simple awk script to calculate the average of values that are printed out a number of times per second (the number of time the printing occurs varies). The data is of the format shown below:
1 4.43
1 3.65
1 2.45
2 7.65
2 8.23
2 5.65
3 4.65
3 6.21
.. ..
120... (4 Replies)
Hi
New to shell script and awk and need assistance on this problem. I need to use a variable to substitute a string in an external file and write the changed info to another file.
At first I did not know if you could use a variable as the sub value but the following showed me that I can.
... (3 Replies)
Hi, I have a very simple script like below:
for n in 10 20 30
do
for a in 30 40 50 60 70 80
do
for r in 2 3 4 5 6 7
do
m=$((r*a))
count=1
while
do
echo "a = " $a ", m = " $m ", n = " $n
... (2 Replies)
Hello;
Trying to figure out how to keep just the contents between the two search lines:
awk '/regexp_1/ ,/regexp_2/'
I do not want lines containing regexp_1 and regexp_2 in the output.
Thank you for any ideas
Video tutorial on how to use code tags in The UNIX and Linux Forums. (5 Replies)
Hello;
I need to print two previous lines after searching for a reg exp:
awk '/haywood/'
should produce the following
===================
p9J46THe020804 89922 Tue Oct 18 21:06 MAILER-DAEMON
(host map: lookup (haywood.com): deferred)
... (1 Reply)
Hi there, Im sure there is a simple explanation for this but I have a file like this with no balnk lines
peter
paul
john
I run the command
# var=`grep paul file.txt`
# echo $var
paul
# echo $var | wc -l
1
but when I grep for a value that isnt in the file, i still... (4 Replies)
Hello;
we have :
awk '/reg_exp/,0/
prints every line after the first occurrence of "reg_exp"
But if I want to print rest of the lines AFTER the last occurrence of "reg_exp",
how would I do it ??
Tried :
awk ' ! (/reg_exp/,0)'
But it errored...
Thank you for any... (5 Replies)
Discussion started by: delphys
5 Replies
LEARN ABOUT BSD
shlock
SHLOCK(1) General Commands Manual SHLOCK(1)NAME
shlock - create lock files for use in shell scripts
SYNOPSIS
shlock -p pid -f name [ -b ] [ -u ] [ -c ]
DESCRIPTION
Shlock tries to create a lock file named name and write the process ID pid into it. If the file already exists, shlock will read the
process ID from the file and test to see if the process is currently running. If the process exists, then the file will not be created.
Shlock exits with a zero status if it was able to create the lock file, or non-zero if the file refers to currently-active process.
OPTIONS-b Process IDs are normally read and written in ASCII. If the ``-b'' flag is used, then they will be written as a binary int. For
compatibility with other systems, the ``-u'' flag is accepted as a synonym for ``-b'' since binary locks are used by many UUCP pack-
ages.
-c If the ``-c'' flag is used, then shlock will not create a lock file, but will instead use the file to see if the lock is held by
another program. If the lock is valid, the program will exit with a non-zero status; if the lock is not valid (i.e., invoking
shlock without the flag would have succeeded), then the program will exit with a zero status.
EXAMPLES
The following example shows how shlock would be used within a shell script:
LOCK=/var/run/innd/LOCK.send
trap 'rm -f ${LOCK} ; exit 1' 1 2 3 15
if shlock -p $$ -f ${LOCK} ; then
# Do appropriate work
else
echo Locked by `cat ${LOCK}`
fi
HISTORY
Written by Rich $alz <rsalz@uunet.uu.net> after a description of HDB UUCP locking given by Peter Honeyman. This is revision 1.9, dated
1996/10/29.
SHLOCK(1)
10-11-2011
