Sometimes, while performing the requested task, GNU tar
notices
some conditions that are not exactly errors, but which the user
should be aware of. When this happens, tar
issues a
warning message describing the condition. Warning messages
are output to the standard error and they do not affect the exit
code of tar
command.
GNU tar
allows the user to suppress some or all of its warning
messages:
Control display of the warning messages identified by keyword. If keyword starts with the prefix ‘no-’, such messages are suppressed. Otherwise, they are enabled.
Multiple --warning messages accumulate.
The tables below list allowed values for keyword along with the warning messages they control.
tar
operationtar --create
‘%s: Unknown file type; file ignored’
‘%s: socket ignored’
‘%s: door ignored’
‘%s: file changed as we read it’
Suppresses warnings about unreadable files or directories. This keyword applies only if used together with the --ignore-failed-read option. See Ignore Failed Read.
tar --extract
‘%s: implausibly old time stamp %s’
‘%s: time stamp %s is %s s in the future’
Controls verbose description of failures occurring when trying to run alternative decompressor programs (see alternative decompression programs). This warning is disabled by default (unless --verbose is used). A common example of what you can get when using this warning is:
$ tar --warning=decompress-program -x -f archive.Z tar (child): cannot run compress: No such file or directory tar (child): trying gzip
This means that tar
first tried to decompress
archive.Z using compress
, and, when that
failed, switched to gzip
.
‘Record size = %lu blocks’