Yes, expr is an external program; the builtin $(( )) is much more efficient.
And in an if [ ${cnt} -eq 0 ]; then you can even do cnt=1.
Further, you can redirect a whole code block like this
And in this case of course
This User Gave Thanks to MadeInGermany For This Post:
Hi,
I am planning to implement a scheduled script that will go against my log files (every hour), search for a set of key words (errors, exceptions, faults etc). The script must be intelligent enough to scan only the new lines added to the log file since it last ran.
I can use grep for... (3 Replies)
Hello,
I'm brand new to this forum. I am working on my first Bash shell script. We were given an exercise to get ready for the real assignment. I could use some help.
The exercise is to "set two variables (i. e., file1 & file2) on the command line to the paths of the text files. We are to... (1 Reply)
Hello,
I have two AIX 5.3 servers that are supposedly set up exactly the same. The problem I am having is on one of the servers, it seems dynamic routes are being added mysteriously and non-periodically. This only happens on one server and not the other. Also, there doesn't seem to be a specific... (1 Reply)
Guys,
I am trying to get unique numbers which i can use as a primary key in a table. I tried using the <seconds_since_epoch>.<hostname> combination but since more than one process can run on the same machine at the same time, this won't be unique either. Can anyone tell me another way to do... (2 Replies)
I'm trying to add a string to the end of each element in an array.
I have filled an array using grep:
for ($i = 0; $i <= $#array} - 1; $i++)
{
push (@data,qx(grep '$array' $file));
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Now i want to add something to the end of the array. For example if my... (3 Replies)
Hello Guys..
I am facing this weird problem of static route not added after reboot!!
Following is my route-<interface> file..
# cat /etc/sysconfig/network-scripts/route-eth0
ADDRESS0=172.31.0.1
NETMASK0=255.255.255.255
GATEWAY0=192.168.208.1
ADDRESS1=172.31.15.2... (3 Replies)
Dear All,
I created a new partition through "Integrated Virtualization Manager" but there have an error when I added a new disk to the partition. The disk already created without any issue,
Below error is to add the disk to the partition
An error occured while modifying the assignments... (5 Replies)
Please could someone have a look at the code below and spot the cause of the error.
Thanks in advance.
CODE BELOW: (code tags now added) My apologies please, that was my first time here.:)
#! /bin/bash
# file: whileloop.sh
arr1=(2 4 6 8)
arr2=(3 6 9 12)
arr3=()
indextotal=(${#arr1})... (4 Replies)
Discussion started by: Chiadi
4 Replies
LEARN ABOUT REDHAT
fb.modes
fb.modes(8) Linux frame buffer utils fb.modes(8)NAME
fb.modes - frame buffer modes file
DESCRIPTION
/etc/fb.modes contains an unlimited number of video mode descriptions. The general format of a video mode is:
mode
geometry <xres> <yres> <vxres> <vyres> <depth>
timings <pixclock> <left> <right> <upper> <lower> <hslen> <vslen>
options <value>
endmode
OPTIONS
geometry options:
xres visible horizontal resolution (in pixels)
yres visible vertical resolution (in pixels)
vxres virtual horizontal resolution (in pixels)
vyres virtual vertical resolution (in pixels)
depth display depth (in bits per pixel)
timing options:
pixclock
length of one pixel (in picoseconds)
left left margin (in pixels)
right right margin (in pixels)
upper upper margin (in pixel lines)
lower lower margin (in pixel lines)
hslen horizontal sync length (in pixels)
vslen vertical sync length (in pixel lines)
other options:
the first value of this options is the default
hsync {low|high}
the horizontal sync polarity
vsync {low|high}
the vertical sync polarity
csync {low|high}
the composite sync polarity
extsync {false|true}
enable or disable external resync. If enabled the sync timings are not generated by the frame buffer device and must be pro-
vided externally instead. Note that this option may not be supported by every frame buffer device
laced {false|true}
enable or disable interlace. If enabled the display will be split in two frames, each frame contains only even and odd lines
respectively. These two frames will be displayed alternating, this way twice the lines can be displayed and the vertical fre-
quency for monitor stays the same, but the visible vertical frequency gets halved
double {false|true}
enable or disable doublescan. If enabled every line will be displayed twice and this way the horizontal frequency can easily
be doubled, so that the same resolution can be displayed on different monitors, even if the horizontal frequency specifica-
tion differs. Note that this option may not be supported by every frame buffer device
INTERNALS
Generally a frame buffer display is organized as follows:
+---+---------------+---+---+
| | ^ | | |
| | | 5 | | |
| | v | | |
+---#################---+---+
| # ^ # | |
| # | # | |
| # | # | |
| 1 # | 2 # 3 | 4 |
|<->#<------+------>#<->|<->|
| # | # | |
| # | 6 # | |
| # | # | |
| # v # | |
+---#################---+---+
| | ^ | | |
| | | 7 | | |
| | v | | |
+---+---------------+---+---+
| | ^ | | |
| | | 8 | | |
| | v | | |
+---+---------------+---+---+
1 left margin
2 xres
3 right margin
4 horizontal sync len
5 upper margin
6 yres
7 lower margin
8 vertical sync len
The area bordered with `#' is the visible display area. Horizontal and vertical frequencies can now easily be calculated, for this the sum
of horizontal or vertical values are important
htotal = left + xres + right + hslen
vtotal = upper + yres + lower + vslen
The length of one line can now be calculated with pixclock
line = pixclock * htotal
and we have the horizontal frequency
hfreq = 1E12 / line = 1E12 / (pixclock * htotal)
To get the vertical frequency vtotal must eventually adjusted. If the display is laced, vtotal must be halved or if the display is a dou-
blescan one, vtotal must be doubled. Now we can calculate the length of one frame
if (lace) vtotal /= 2
if (double) vtotal *= 2
frame = vtotal * line
and we get also the vertical frequency
vfreq = 1E12 / frame = hfreq / vtotal
SEE ALSO fbset(8), fbdev(4)local Aug 1996 fb.modes(8)