You have been handed backup.tar and want to see what it contains before unpacking anything. Which command lists the archive's contents without extracting it?
LPIC-1 Exam 101-500, objective 103. GNU and Unix commands medium
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The options
Correct tar -tf backup.tar
Correct. -t lists the archive members and -f names the archive file. Add -v for a long listing with permissions, owner and size.
Not correct tar -xf backup.tar
Wrong. -x extracts, writing the archive's files into the current directory and overwriting anything with the same name.
Not correct tar -cf backup.tar
Wrong. -c CREATES an archive rather than reading one. With no files named, GNU tar refuses ('Cowardly refusing to create an empty archive') and backup.tar survives, but add any file operand and this command overwrites the archive you were trying to inspect.
Not correct tar -rf backup.tar
Wrong. -r appends files to the end of an existing uncompressed archive; it does not list anything.
Why
tar's mode letter comes first and there is exactly one per invocation: -c create, -x extract, -t list, -r append, -u update. -f must be followed by the archive name. Compression is a separate switch: -z gzip, -j bzip2, -J xz. Modern GNU tar can detect the compression on extraction, but naming it explicitly always works.
Where this comes from
- Cited
- LPI exam objective 103.3
- What it says
- Create, list and extract tar archives.
Practise this
Reading one question is not practice. The trainer will draw a set from objective 103 and space the ones you get wrong.