UNIX for Dummies Questions & Answers

Code:

tar -zcf file.tar.gz *.txt

hi corona,

I am using the below commands (in a single line) in my script to tar the files as per your suggestion.

I see a *.tar.gz in the path I am running the script. But I thought the tar file to be in /opt/informatica/infa_shared/SrcFiles/arch path. can you please advice?

Also, I would like to unzip/untar back the files to verify if the files are tar-red properly.. and used the below command from command line. It actually returns me the path - /opt/informatica/infa_shared/SrcFiles/arch but there are no files extracted... I am expecting to see the files individually.. can you help on how to extract the files?

I have LINUX OS.

thanks!

tar does not read from standard input.

tar works the way I showed you, not the way you're trying to use it.

Since you refuse to explain any of the details, I still have no idea what you're even trying to do. I also asked what your system was and received no answer. This information is needed to answer some of your questions.

Why would the tar file be in /opt/informatica/infa_shared/SrcFiles/arch when you told tar to read files from /opt/informatica/infa_shared/SrcFiles/arch ? It ends up in the current directory because you didn't tell it anything else.

There is also much useless use of ls * in your code. ls is not the thing that understands *, any command is given the corresponding filenames when you use *. You might as well just put the * where you want the filenames to appear in the first place -- which is, as I demonstrated, the last arguments of tar.

You also have lots of unbracketed variables which are going to screw up. _$DATE_OF_RUN_$OTHER will mess up because you have no variable named $DATE_OF_RUN_. You use ${VARNAME} style brackets to defeat that.

I'll venture a third try at what I'm guessing you want:

Code:

TARFILE="/opt/informatica/infa_shared/SrcFiles/arch/${ENVID}_$(date +"%Y%m%d%H%M%S").tar.gz"
# Create the compressed tar file
tar -zcf "${TARFILE}" "${ENVID}_"*"_${DATE_OF_RUN}.${ENVID}_"*".TXT"
# List files inside the tar file
tar -ztf "${TARFILE}" > ${LOGFILE}

And again, if you tell me what your system is, there may or may not be a 'verify' option that would be of use to you. But there's no point pointing it out if you don't have it. What is your system?

Hi Corona,

I am very new to Unix that's why I have hiccups..

My machine is Linux OS.

My requirement is to take some files from landing directory (there will be many files, but I need to pick the files based on the date - the date value is stored in another file) and then archive them to another directory. As I have to pick only certain files, I used ls command to get a list of them.

This is just to back up the files and if the need be, the tar files from the archive directory has to be used and the individual files (like how it was initially) are taken from it and to be sent to landing directory for processing the files.

As it would occupy less space by ZIP ing them, I was trying to zip the files separately and store all the files to a single tar file.

I was told to zip them all individually and tar the zip-ped files into a single tar file. But, I remember that you said it is done the other way round. I am fine with it as long as I can untar and unzip the files and bring them back as individual files (like how it was)...

I will make the bracket changes you mentioned.

Thanks much!!

Thank you. You can use your version of tar to verify while it's creating the tarball, then, by doing tar --verify ....

The usual procedure is the opposite -- compress the tar. This also does a better job of preserving the file's permissions, something pure tar is very good at; if you went and mangled all the files by zipping them first, how well that'd work is anyone's guess. Doing it the other way around means you can extract them directly, and not have to unzip them individually. And you get good compression either way, especially with text files.

Hi Corona,

With TAR verify, will I be able to extract the files back from the .tar.gz file?

eg., I create a .tar.gz file on all the below files. After I execute my script, I see that the .tar.gz file is created. Now, I want to execute some commands and see that I am able to extract all the below files individually, like how they are below. I want to untar / unzip to get the individual files, do you know if this is achievable?

PHP Code:

-rw-r--r-- 1 z06189 bi 16061 Jan 30 16:33 FERAL_CONTROL_20120115.FERAL_CTRL.txt
-rw-r--r-- 1 z06189 bi     0 Jan 31 11:46 FERAL_CONTROL_20120131.FERAL_CNTRL.TXT
-rw-r--r-- 1 z06189 bi   135 Jan 31 13:14 FERAL_CONTROL_20121213.FERAL_CTRL.TXT
-rw-r--r-- 1 z06189 bi   194 Jan 31 11:53 FERAL_DATA1_20120131.FERAL_DATA.TXT
-rw-r--r-- 1 z06189 bi   102 Jan 31 13:20 FERAL_DATA1_20121213.FERAL_98312.TXT
-rw-r--r-- 1 z06189 bi    91 Jan 31 11:53 FERAL_DATA_20120131.FERAL_CNTRL.TXT 


also, I used the TAR verify on the command prompt, but was not successful.
below are the commands... can you help?

PHP Code:

sh-3.2$ tar -xW verify FERAL_20120201125930.tar.gz
tar: Cannot verify stdin/stdout archive
tar: Error is not recoverable: exiting now
sh-3.2$ tar -tW verify FERAL_20120201125930.tar.gz
tar: Cannot verify stdin/stdout archive
tar: Error is not recoverable: exiting now
sh-3.2$ tar -cW verify FERAL_20120201125930.tar.gz
tar: Cannot verify stdin/stdout archive
tar: Error is not recoverable: exiting now 


You extract the files with tar -C /path/to/destination/folder/ -zxf filename.tar.gz

You really need to read more carefully.

1) It's not verify, it's --verify.
2) You use it when creating the archive. It's not an extra step. Just add --verify in front when creating the archive.

Also, since the files are .tar.gz hence already compressed, you need the -z flag.