How Do I Pass The Command Line Errors To A File.

hi,

I am newbie in Linux shell scripting.Can anybody help me to check the presence of file identified by variable in Shell scripting?

For example: I am reading the content of a file using while command as below:
"while read -r line
do
code block
done < file_name"

Now in this case every line in file gets stored in the variable 'line' one by one.Problem here is every line in the file is nothing but the file_path of another file say xyz.txt and I am checking presence of this xyz.txt file using below command:
if [-f $line]
as 'line' is the variable which stores file path of xyz.txt but it is not working. It is unable to check the presence of this xyz.txt file as i am addressing it with the variable 'line'.

Please help me.Thanks in advance.

Hello--

I'm trying to locate a file or a command line in a file on my hard drive. I am running Ubuntu 12.05.4 linux. Is there a grep command that will search the whole tree from root down to all the sub-directories?

Thank You.

When working with a virtual terminal, I find it often easier to edit a file to execute than to construct a regular-expression etc. to inject the right UUID etc. into the command. I have run into an error while doing this. I suspect it is stems from quote mishandling, or improper escape sequences. (I ran directly from the command line earlier, forgot a quotation mark, and it gave a similar bad result.)
The program in question was efibootmgr. I had a file vaguely similar to this one, named efiboot.Hz:
Code:

efibootmgr -c -g -L "Debian (EFI stub)" -l '\EFI\debian\vmlinuz' -u 'root=UUID=$UUID ro quiet rootfstype=ext4 add_efi_memmap initrd=\\EFI\\debian\\initrd.img'
efibootmgr -c -d /dev/sdb -L "Debian Linux" -l '\EFI\debian\vmlinuz' -u 'root=UUID=1234-ffff-789 ro quiet rootfstype=ext4 add_efi_memmap initrd=\\EFI\\debian\\initrd.img'

Then I executed:
Code:

`tail -n 1 efiboot.Hz`

efibootmgr -v revealed the previous command produced a garbled name and boot options, and most importantly it didn't boot. Manually writing the last line on the terminal did produce the desired effect. I thought I checked the output from tail before putting the back-ticks.
What did I do wrong?

HI,

I am a newbie to Linux and am trying to create a pipe file with the below command:

mkfifo pone

Now I am trying to write data to the file with the following command on the command prompt:

echo asdadsasdasdasdasdasd >./pone

But after i enter this command- the screen hangs up and doesnt proceed ahead.
Same thing happened when I tried writing using:
gedit pone


Can anyone help me resolve this issue?

Hi,

I have been trying to get information on how to process the output of a tcl file (aodv and leach protocol using mannasim) which I got on my command line Iinterface. Actually, I don't even know the keywords to search as I am new to this and other minor attempts haven't yielded positive results., I know there is usually a trace file but I can't see any. All I see is on my command line.

I also observe that it took the space on the entire screen and I can't copy the output from the start ( I could only copy from node 19 out of 30 nodes) because of the huge number of output lines.

The last thing I havent been able to figure ou is whether temperature is equivalent to energy Iin mannasim as mannasim has only temperature and carbon dioxide?


Thanks

I have a VPS and it has SSH access.

Is there some way that I can do command line on my VPS without having root access?

(I would like to start learning Linux command line!)


Rob

SUSE 11. I have issued the command "gzip -r -c directory > archive.gz" over a complete directory tree. I've got no errors or warnings. I can decompress the gz file also without errors, but what I get is a single file which is the concat of all of the original files, including binaries, without posibility of splitting them into the original ones.

I suppose I've lost my files, no?.

Secondary question: why does gzip let me issue that destructive command?

when a command is typed(i.e. /path/to/the/program), as a normal user, he should be able to run that command , execute that program as ROOT and log out root after the execution is completed.
Only one user should be able to do it.
Hence, I have created a new user vj and added the following command in visudo:
Code:

vj ALL=(ALL) NOPASSWD: /path/to/the/program

Now user vj will be able to typein the command.

What I need is that the program which is been called must run as if it is run by a root user,and when the program is completely executed, exit the root user.

How do I proceed?

Hello all, I am new to Linux (apparently) and am taking a intro course to the OS. My terminal does not support info or man for the cd command and I would like to know: If you won't find the cd command in either /bin or /usr/bin, or in any directory listed in the PATH setting. How is it executed then? (That is, if there is no cd executable, why doesn't this command cause a “command not found” error?)

Thanks for any help!

I know that '>' and '>>' will redirect output to a file

However, how does one keep this output on the same line as the previous line?

'echo -n' will stop a trailing new line but for terminal redirection?