10 More Discussions You Might Find Interesting
1. Shell Programming and Scripting
Ultimate goal is to delete lines from before and after a block of lines in a given file. First attempt was something like this:
sed -e '1,/STARTUP/ d' inputfile.txt > outputfile.txt
but that deleted everything down to and including the line with STARTUP. I need to delete everything before... (6 Replies)
Discussion started by: edstevens
6 Replies
2. Shell Programming and Scripting
if ! grep -q "aa" $line;then
if ! grep -q "bb" $line;then
somthing
fi
fi (2 Replies)
Discussion started by: yanglei_fage
2 Replies
3. Shell Programming and Scripting
How do you get the contents of a line directly after a selected one? Also, how about before it? I am using CSH and don't have any GNU products installed.
Input file:
apple
orange
plum
So say I use grep on orange...how do I get plum (this line can be different so I can't just grep... (4 Replies)
Discussion started by: thibodc
4 Replies
4. UNIX Desktop Questions & Answers
i have a line that has ",,", i need to change it to "," ; But i have it more than one time in the same line , sub(",,",",",$0) just sub the first one in the line?
---------- Post updated at 08:15 AM ---------- Previous update was at 08:15 AM ----------
using AWK please (2 Replies)
Discussion started by: Reham.Donia
2 Replies
5. Shell Programming and Scripting
hi! i researched about comparing two columns here and got an answer. but after examining my two files, i found out that the first columns of the two files are not unique with each other. all i want to compare is the 2nd and 3rd column.
FILE 1:
ABS 456 315
EBS 923 163
JYQ3 654 237
FILE 2:... (1 Reply)
Discussion started by: engr.jay
1 Replies
6. Shell Programming and Scripting
I want to delete a line between selected lines using sed:
e.g. : Between "bus" to "pins", delete lines conaining "signal" word.
Input :
bus
direction
signal new
signal old
pins
signal ok
end
Desired Output:
bus
direction
pins
signal
end (4 Replies)
Discussion started by: nehashine
4 Replies
7. Shell Programming and Scripting
Hello,
I want to change a line at file whit a script
i want to change line 150 for example, write hello and remove text of this line
EXAMPLE
LINE 150: my mother
change to:
LiNE 150: HELLO (4 Replies)
Discussion started by: uri_crack
4 Replies
8. Shell Programming and Scripting
I am trying to print 1st, 2nd, 13th and 14th fields of a file of line numbers from 29 to 10029. I dont know how to put this in one code. Currently I am removing the selected lines by
awk 'NR==29,NR==10029' File1 > File2
and then doing
awk '{print $1, $2, $13, $14}' File2 > File3
Can... (3 Replies)
Discussion started by: ananyob
3 Replies
9. Shell Programming and Scripting
Hello Experts,
I am working on a small file editing script. Since all experts here are very generous to give me the complete code, I would take up the problem in steps so that I ensure my opportunity to learn.
AIM: The script has some commented and some uncommented lines. I need to :
... (2 Replies)
Discussion started by: hkansal
2 Replies
10. Shell Programming and Scripting
Hi,
I'm struggling to write a script to do the following,
-will go through each line in the file
-in a specific character positions, changes
the value to a new value
-These character positions are fixed througout the file
-----------------------
e.g.: file1.sh will have the following 3... (4 Replies)
Discussion started by: vini99
4 Replies
CRONTAB(1) User Commands CRONTAB(1)
NAME
crontab - maintains crontab files for individual users
SYNOPSIS
crontab [-u user] file
crontab [-u user] [-l | -r | -e] [-i] [-s]
crontab -n [ hostname ]
crontab -c
DESCRIPTION
Crontab is the program used to install, remove or list the tables used to serve the cron(8) daemon. Each user can have their own crontab,
and though these are files in /var/spool/, they are not intended to be edited directly. For SELinux in MLS mode, you can define more
crontabs for each range. For more information, see selinux(8).
In this version of Cron it is possible to use a network-mounted shared /var/spool/cron across a cluster of hosts and specify that only one
of the hosts should run the crontab jobs in the particular directory at any one time. You may also use crontab(1) from any of these hosts
to edit the same shared set of crontab files, and to set and query which host should run the crontab jobs.
Running cron jobs can be allowed or disallowed for different users. For this purpose, use the cron.allow and cron.deny files. If the
cron.allow file exists, a user must be listed in it to be allowed to use cron If the cron.allow file does not exist but the cron.deny file
does exist, then a user must not be listed in the cron.deny file in order to use cron. If neither of these files exists, only the super
user is allowed to use cron. Another way to restrict access to cron is to use PAM authentication in /etc/security/access.conf to set up
users, which are allowed or disallowed to use crontab or modify system cron jobs in the /etc/cron.d/ directory.
The temporary directory can be set in an environment variable. If it is not set by the user, the /tmp directory is used.
OPTIONS
-u Appends the name of the user whose crontab is to be modified. If this option is not used, crontab examines "your" crontab, i.e.,
the crontab of the person executing the command. Note that su(8) may confuse crontab, thus, when executing commands under su(8) you
should always use the -u option. If no crontab exists for a particular user, it is created for him the first time the crontab -u
command is used under his username.
-l Displays the current crontab on standard output.
-r Removes the current crontab.
-e Edits the current crontab using the editor specified by the VISUAL or EDITOR environment variables. After you exit from the editor,
the modified crontab will be installed automatically.
-i This option modifies the -r option to prompt the user for a 'y/Y' response before actually removing the crontab.
-s Appends the current SELinux security context string as an MLS_LEVEL setting to the crontab file before editing / replacement occurs
- see the documentation of MLS_LEVEL in crontab(5).
-n This option is relevant only if cron(8) was started with the -c option, to enable clustering support. It is used to set the host in
the cluster which should run the jobs specified in the crontab files in the /var/spool/cron directory. If a hostname is supplied,
the host whose hostname returned by gethostname(2) matches the supplied hostname, will be selected to run the selected cron jobs
subsequently. If there is no host in the cluster matching the supplied hostname, or you explicitly specify an empty hostname, then
the selected jobs will not be run at all. If the hostname is omitted, the name of the local host returned by gethostname(2) is
used. Using this option has no effect on the /etc/crontab file and the files in the /etc/cron.d directory, which are always run,
and considered host-specific. For more information on clustering support, see cron(8).
-c This option is only relevant if cron(8) was started with the -c option, to enable clustering support. It is used to query which
host in the cluster is currently set to run the jobs specified in the crontab files in the directory /var/spool/cron , as set using
the -n option.
SEE ALSO
crontab(5), cron(8)
FILES
/etc/cron.allow
/etc/cron.deny
STANDARDS
The crontab command conforms to IEEE Std1003.2-1992 (``POSIX''). This new command syntax differs from previous versions of Vixie Cron, as
well as from the classic SVR3 syntax.
DIAGNOSTICS
An informative usage message appears if you run a crontab with a faulty command defined in it.
AUTHOR
Paul Vixie <vixie@isc.org>
Colin Dean <colin@colin-dean.org>
cronie 2012-11-22 CRONTAB(1)