How to check if a Unix tar gz file is a valid file without uncompressing

Question

I have found the question How to determine if data is valid tar file without a file   but I was wondering  is there a ready made command line solution

User · Answer

These are all very sub-optimal solutions. From the GZIP spec

ID2 (IDentification 2)
These have the fixed values ID1 = 31 (0x1f, \037), ID2 = 139 (0x8b, \213), to identify the file as being in gzip format.

Has to be coded into whatever language you're using.

User · Answer

If you want to do a real test extract of a tar file without extracting to disk  use the -O option  This spews the extract to standard output instead of the filesystem  If the tar file is corrupt  the process will abort with an error   Example of failed tar ball test       echo  this will not pass the test   gt  hello tgz   tar -xvzf hello tgz -O  gt   dev null gzip  stdin  not in gzip format tar  Child returned status 1 tar  Error exit delayed from previous errors   rm hello     Working Example       ls hello  ls  hello   No such file or directory   echo  hello1   gt  hello1 txt   echo  hello2   gt  hello2 txt   tar -cvzf hello tgz hello 12  txt hello1 txt hello2 txt   rm hello 12  txt   ls hello  hello tgz   tar -xvzf hello tgz -O hello1 txt hello1 hello2 txt hello2   ls hello  hello tgz   tar -xvzf hello tgz hello1 txt hello2 txt   ls hello  hello1 txt  hello2 txt  hello tgz   rm hello

User · Answer

A nice option is to use tar -tvvf  lt filePath gt  which adds a line that reports the kind of file   Example in a valid  tar file    gt  tar -tvvf filename tar  drwxr-xr-x  0 diegoreymendez staff       0 Jul 31 12 46   testfolder2  -rw-r--r--  0 diegoreymendez staff      82 Jul 31 12 46   testfolder2    DS Store -rw-r--r--  0 diegoreymendez staff    6148 Jul 31 12 46   testfolder2  DS Store drwxr-xr-x  0 diegoreymendez staff       0 Jul 31 12 42   testfolder2 testfolder  -rw-r--r--  0 diegoreymendez staff      82 Jul 31 12 42   testfolder2 testfolder    DS Store -rw-r--r--  0 diegoreymendez staff    6148 Jul 31 12 42   testfolder2 testfolder  DS Store -rw-r--r--  0 diegoreymendez staff  325377 Jul  5 09 50   testfolder2 testfolder Scala pages Archive Format  POSIX ustar format   Compression  none   Corrupted  tar file    gt  tar -tvvf corrupted tar  tar  Unrecognized archive format Archive Format   null    Compression  none tar  Error exit delayed from previous errors

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What about just getting a listing of the tarball and throw away the output  rather than decompressing the file   tar -tzf my tar tar gz  gt  dev null   Edited as per comment  Thanks zrajm   Edit as per comment  Thanks Frozen Flame  This test in no way implies integrity of the data  Because it was designed as a tape archival utility most implementations of tar will allow multiple copies of the same file

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use the -O option        If the tar file is corrupt  the process will abort with an error    Sometimes yes  but sometimes not  Let s see an example of a corrupted file   echo Pete  gt  my name tar -cf my data tar my name        Simulate a corruption sed  lt  my data tar  s Pete Fool    gt  my data now tar       my data now tar  is the corrupted file  tar -xvf my data now tar -O   It shows     my name Fool     Even if you execute  echo      tar said that there was no error   0   but the file was corrupted  it has now  Fool  instead of  Pete

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You can also check contents of   tag gz file using pigz  parallel gzip  to speedup the archive check   pigz -cvdp number of threads       path      archive name tar gz   tar -tv  gt   dev null

User · Answer

you could probably use the gzip -t option to test the files integrity   http   linux about com od commands l blcmdl1 gzip htm  from  http   unix ittoolbox com groups technical-functional shellscript-l how-to-test-file-integrity-of-targz-1138880  To test the gzip file is not corrupt   gunzip -t file tar gz   To test the tar file inside is not corrupt   gunzip -c file tar gz   tar -t  gt   dev null   As part of the backup you could probably just run the latter command and check the value of    afterwards for a 0  success  value  If either the tar or the gzip has an issue     will have a non zero value

User · Answer

I have tried the following command and they work well   bzip2 -t file bz2 gunzip -t file gz   However  we can found these two command are time-consuming  Maybe we need some more quick way to determine the intact of the compress files

[gzip] How to check if a Unix .tar.gz file is a valid file without uncompressing?

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