So, im making a small script to do an entire task for me. The task is to get the output of the dmidecode -Fn into a text file and then take a part of the dmidecode output, in my example, the Address (0xE0000) as the file name of the txt.
My script goes as follows and does work, i have tested it. The only little issue that i have, is that the file name of the txt appears as "? 0xE0000.txt"
My question is, why am i getting a question mark followed by a space in the name?
#!/bin/bash
directory=$(pwd)
name=$(dmidecode|grep -i Address|sed 's/Address://')
inxi -Fn > $directory/"$name".txt
The quotes in the "$name".txt is to avoid an "ambiguous redirect" error i got when running the script.
Update #Just Somebody
root#server:/home/user/Desktop# dmidecode | sed -n 's/Address://p'
0xE0000
root#server:/home/user/Desktop#
Solution
The use of |sed -n 's/^.*Address:.*0x/0x/p' got rid of the "? " in 0xE0000.txt
A big thanks to everyone!
You've got a nonprinting char in there. Try:
dmidecode |grep -i Address|sed 's/Address://'| od -c
to see exactly what you're getting.
UPDATE: comments indicate there's a tab char in there that needs to be cleaned out.
UPDATE 2: the leading tab is before the word Address. Try:
name=$(dmidecode |grep -i Address|sed 's/^.*Address:.*0x/0x/')
or as #just_somebody points out:
name=$(dmidecode|sed -n 's/^.*Address:.*0x/0x/p')
UPDATE 3
This changes the substitution regex to replace
^ (start of line) followed by .* (any characters (including tab!)) followed by Address: followed by .* (any characters (including space!)) followed by 0x (which are always at the beginning of the address since it's in hex)
with
0x (because you want that as part of the result)
If you want to learn more, read about sed regular expressions and substitutions.
Related
I'm using a shell & TCL script to login to a switch and get the output of certain commands and in some places I can see ^D coming up. I tried to use the dos2unix utility but still it didn't go away.
Eth1/37 NOM: xcvrAbsen routed auto auto --
^DEth1/38 NOM: xcvrAbsen routed auto auto --
Eth1/39 NOM: xcvrAbsen routed auto auto --
Eth101/1/45 eth 1000 NOM:NO_PATCHING CABLE
^DEth101/1/46 eth 1000 NOM:NO_PATCHING CABLE
Eth101/1/47 eth 1000 NOM:NO_PATCHING CABLE
How can this be eliminated, are there any standard tools like dos2unix which can get rid of such data?
What I'm trying to do is to compare two files which are from the same switch and the same command and the same output, but due to these ^D, Vimdiff shows it as different lines.
How to get this eliminated?
Command I'm using is something like this:
$cdir/ciscocmd -Y -u $operator -p $password -s $password -t $switch -r rfc_sa_commands | sed 's/^^D//' > $switch.$NOW
dos2unix removes carriage returns, no other control characters.
The tool to remove all occurrences of an arbitrary character is called tr.
tr -d '\004' <inputfile >outputfile
This assumes you have literal ctrl-D characters, not sequences of caret ^ and D. The tr utility cannot remove a specific sequence; it just processes individual characters. To remove a sequence, you'd need
sed 's/\^D//g' inputfile >outputfile
where the backslash is required because the caret alone has a special meaning in regular expressions (it matches beginning of line). Doubling it does not escape it; ^^ probably still just matches beginning of line, though it's not really well-defined, and could introduce apparently random behavior.
Even if the special character is visible as '^D', it may be NOT catchable like this.
Interesting readings, are:
https://en.wikipedia.org/wiki/ASCII#Character_groups
https://en.wikipedia.org/wiki/End-of-Transmission_character
I think a way to do it would be:
<your command>|sed -e 's/\x04//g'
Does it solve your issue?
\#Add another new line of text to hosts and send the output to
hosts_update.sh
sed '/localhost/a\
# Gateway
10.0.0.1 it20.it.cs.umb.edu it20
# Addresses for the Windows PCs
10.0.0.240 it21.it.cs.umb.edu it21\
10.0.0.241 it22.it.cs.umb.edu it22\
10.0.0.242 it23.it.cs.umb.edu it23\
10.0.0.243 it24.it.cs.umb.edu it24\
10.0.0.244 it25.it.cs.umb.edu it25\
10.0.0.245 it26.it.cs.umb.edu it26\
10.0.0.246 it27.it.cs.umb.edu it27\
10.0.0.247 it28.it.cs.umb.edu it28\
' hosts > hosts_update.sh
First things first, your initial couple of lines look way off for a shell script. It looks like your hosts_update.sh line should be part of the comments (and the comment shouldn't start with a \ anyway):
# Add another new line of text to hosts and send the output
# to hosts_update.sh
Secondly, you need a \ at the end of each line that you're appending with sed, at the moment you only have it on certain select lines. With that in mind, this script is probably what you wanted:
# Add another new line of text to hosts and send the output
# to hosts_update.sh
sed '/localhost/a\
\
# Gateway\
10.0.0.1 it20.it.cs.umb.edu it20\
\
# Addresses for the Windows PCs\
10.0.0.240 it21.it.cs.umb.edu it21\
10.0.0.241 it22.it.cs.umb.edu it22\
10.0.0.242 it23.it.cs.umb.edu it23\
10.0.0.243 it24.it.cs.umb.edu it24\
10.0.0.244 it25.it.cs.umb.edu it25\
10.0.0.245 it26.it.cs.umb.edu it26\
10.0.0.246 it27.it.cs.umb.edu it27\
10.0.0.247 it28.it.cs.umb.edu it28\
' hosts > hosts_update.sh
What's actually happening in your case (without the \ continuation characters):
sed '/localhost/a\
# Gateway
10.0.0.1 it20.it.cs.umb.edu it20
is that:
you append a single blank line after localhost;
then you have a sed comment line;
then you tell sed to execute . on line number ten.
At that point, sed rightly complains it has no idea what to do with the . command :-)
I'd say, based on experience, an earlier (working) iteration of the script had only the it21-28 lines and someone added (badly) the it20 and comment/blank lines. That's based on the fact only those lines are the errant ones. However, that's just (informed) speculation and doesn't affect the answer.
And, finally, you probably don't want to call the resultant file hosts_update.sh, people will almost certainly think it's a shell script rather than the hosts file it actually is.
I am not that good on linux shell script and I need little help.
I want to edit a file via script (finding the line and edit).
The Original line is:
# JVM_OPTS="$JVM_OPTS -Djava.rmi.server.hostname=< hostname >"
I want to uncomment and replaye hostname with 127.0.0.1
JVM_OPTS="$JVM_OPTS -Djava.rmi.server.hostname=127.0.0.1"
You can refer to the set command, change the filename with the name you are working at,
sed -i 's## JVM_OPTS="$JVM_OPTS -Djava.rmi.server.hostname=< hostname >"#JVM_OPTS="$JVM_OPTS -Djava.rmi.server.hostname=127.0.0.1"#' filename
Fine answers, but they don't do anything by way of TEACHING the gentleman how and why it works.
If you were using the mundane text editor, ed, you would use three commands after invoking the command "ed filename":
s/^# //
s/< hostname>/127.0.0.1/
w
So, you can use a pipe to submit those commands directly to ed, specifying "-" as its first argument so that it doesn't bother you by reporting character counts upon reading in and writing out the file:
( echo 's/^# //'; echo 's//127.0.0.1/'; echo w ) | ed - filename
You don't need to echo 'q' also because ed will automatically quit when it runs out of input or encounters "end of file" (you can simulate this on the keyboard by just hitting the CTRL-D key rather than actually typing q ).
Here's one way to do it:
sed -i -e 's/# \(JVM_OPTS=.*=\).*/\1127.0.0.1"/' path/to/file
That is, replace the line with the text captured within the group \(JVM_OPTS=.*=\), so everything from JVM_OPTS= until another = sign, and append 127.0.0.1" to the end.
If there might be other lines in the file starting with # JVM_OPTS=,
then you could make the pattern matching more strict, for example:
sed -i -e 's/# \(JVM_OPTS="$JVM_OPTS -Djava.rmi.server.hostname=\).*/\1127.0.0.1"/' path/to/file
I'm currently working on a Unix box and came across this post which I found helpful, in order to learn about cat command in Unix. At the bottom of the page found this line saying: -A = Equivalent to -vET
As I'm new into Unix, I'm unaware of what does this mean actually? For example lets say I've created a file called new using cat and then apply this command to the file:
cat -A new, I tried this command but an error message comes up saying it's and illegal option.
To cut short, wanted to know what does cat -A really mean and how does it effect when I apply it to a file. Any help would be appreciated.
It means show ALL.
Basically its a combination of -vET
E : It will display '$' at the end of every line.
T : It will display tab character as ^I
v : It will use ^ and M-notation
^ and M-notation:
(Display control characters except for LFD(LineFeed or NewLine) and TAB using '^' notation and precede characters that have the high bit set with
'M-') M- notation is a way to display high-bit characters as low bit ones by preceding them with M-
You should read about little-endian and big-endian if you like to know more about M notation.
For example:
!http://i.imgur.com/0DGET5k.png?1
Check your manual page as below and it will list all options avaialable with your command and check is there -A present, if it is not present it is an illegal option.
man cat
It displays non-printing characters
In Mac OS you need to use -e flag and
-e Display non-printing characters (see the -v option), and display a dollar sign (`$') at the end of each line.
I am trying to understand how
sed 's/\^\[/\o33/g;s/\[1G\[/\[27G\[/' /var/log/boot
worked and what the pieces mean. The man page I read just confused me more and I tried the info sai Id but had no idea how to work it! I'm pretty new to Linux. Debian is my first distro but seemed like a rather logical place to start as it is a root of many others and has been around a while so probably is doing stuff well and fairly standardized. I am running Wheezy 64 bit as fyi if needed.
The sed command is a stream editor, reading its file (or STDIN) for input, applying commands to the input, and presenting the results (if any) to the output (STDOUT).
The general syntax for sed is
sed [OPTIONS] COMMAND FILE
In the shell command you gave:
sed 's/\^\[/\o33/g;s/\[1G\[/\[27G\[/' /var/log/boot
the sed command is s/\^\[/\o33/g;s/\[1G\[/\[27G\[/' and /var/log/boot is the file.
The given sed command is actually two separate commands:
s/\^\[/\o33/g
s/\[1G\[/\[27G\[/
The intent of #1, the s (substitute) command, is to replace all occurrences of '^[' with an octal value of 033 (the ESC character). However, there is a mistake in this sed command. The proper bash syntax for an escaped octal code is \nnn, so the proper way for this sed command to have been written is:
s/\^\[/\033/g
Notice the trailing g after the replacement string? It means to perform a global replacement; without it, only the first occurrence would be changed.
The purpose of #2 is to replace all occurrences of the string \[1G\[ with \[27G\[. However, this command also has a mistake: a trailing g is needed to cause a global replacement. So, this second command needs to be written like this:
s/\[1G\[/\[27G\[/g
Finally, putting all this together, the two sed commands are applied across the contents of the /var/log/boot file, where the output has had all occurrences of ^[ converted into \033, and the strings \[1G\[ have been converted to \[27G\[.