tar has the -T operand for reading patterns from a file.
Is there any way to read patterns from stdin, without creating a temp file? I would like to avoid iterating over the archive repeatedly (e.g. with a loop or xargs) as this is a large archive and we're only extracting a small number of specific files.
Shell is sh (ash) or csh.
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Hi.
Here's an example with tar using the often-found idiom of minus "-" to signify STDIN. The input can then be from a here document, q.v., or from the keyboard. The input would be the name of a file, one per line. I would not say a pattern, however, as in filename expansion (so-called globbing), or regular expressions, unless you also use option --wildcards
Code:
#!/usr/bin/env dash
# @(#) s1 Demonstrate tar -T with STDIN as here document, keyboard.
# The Debian Almquist Shell (dash) is a lightweight
# POSIX-compliant shell derived from ash.
#-T, --files-from F
# get names to extract or archive from file F
pe() { for i;do printf "%s" "$i";done; printf "\n"; }
pl() { pe;pe "-----" ;pe "$*"; }
# Remove debris from previous runs.
rm -f t?
pl " Contents of f.tar:"
tar tvf f.tar
pl " Files named t? before operation:"
ls -lgG t?
pl " Extract t2, as directed by a here document:"
tar xvf f.tar -T - <<'EOF'
t2
EOF
pl " Files named t? after operation:"
ls -lgG t?
exit 0
# As interactive:
# enter names, finish with EOF character, usually ^D, (control-D).
tar xvf f.tar -T -
producing:
Code:
% ./s1
-----
Contents of f.tar:
-rw-r--r-- backup/backup 4 2010-07-25 06:47 t1
-rw-r--r-- backup/backup 4 2010-07-25 06:47 t2
-----
Files named t? before operation:
ls: cannot access t?: No such file or directory
-----
Extract t2, as directed by a here document:
t2
-----
Files named t? after operation:
-rw-r--r-- 1 4 Jul 25 06:47 t2
This was run in the environment:
Code:
OS, ker|rel, machine: Linux, 2.6.26-2-amd64, x86_64
Distribution : Debian GNU/Linux 5.0
tar (GNU tar) 1.20
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