Recently I was trying to install Python 2.5 on a CentOS 5 OpenVZ VE. I found a blog post over on the blog.bashton.com site that provided some RPMS but they were for the x86_64 architecture and I needed them for i386. Not to worry, they also provided a SRPM so I could just hit it with rpmbuild.
Now I’m a keyboard and shell kind of guy but I’m lazy. So anytime I can take the output from one command and use it as arguments into another command I’m all for it. Here is a cool trick where I can take the output from the rpmbuild of the python 2.5 SRPM and create a list of all the packages that I need to yum install.
The victim
Doing the rpmbuild of a SRPM returns this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | % rpmbuild --rebuild python25-2.5.1-bashton1.src.rpm 2>&1 | grep "is needed" | sed 's/^[ \t]\+//g' readline-devel is needed by python25-2.5.1-bashton1.i386 openssl-devel is needed by python25-2.5.1-bashton1.i386 gmp-devel is needed by python25-2.5.1-bashton1.i386 ncurses-devel is needed by python25-2.5.1-bashton1.i386 gdbm-devel is needed by python25-2.5.1-bashton1.i386 zlib-devel is needed by python25-2.5.1-bashton1.i386 expat-devel is needed by python25-2.5.1-bashton1.i386 libGL-devel is needed by python25-2.5.1-bashton1.i386 tk is needed by python25-2.5.1-bashton1.i386 tix is needed by python25-2.5.1-bashton1.i386 gcc-c++ is needed by python25-2.5.1-bashton1.i386 libX11-devel is needed by python25-2.5.1-bashton1.i386 glibc-devel is needed by python25-2.5.1-bashton1.i386 pkgconfig is needed by python25-2.5.1-bashton1.i386 tcl-devel is needed by python25-2.5.1-bashton1.i386 tk-devel is needed by python25-2.5.1-bashton1.i386 tix-devel is needed by python25-2.5.1-bashton1.i386 bzip2-devel is needed by python25-2.5.1-bashton1.i386 sqlite-devel is needed by python25-2.5.1-bashton1.i386 autoconf is needed by python25-2.5.1-bashton1.i386 db4-devel >= 4.3 is needed by python25-2.5.1-bashton1.i386 tcl is needed by python25-2.5.1-bashton1.i386 |
Here we’re picking out all the lines that contain “is needed” with this: grep “is needed”. Next we’re cutting out any spaces or tabs that prefix each line with this command: sed ‘s/^[ \t]\+//g’.
Pre magic
Next we can use a quick awk “{ print $1 }” to truncate everything after the package names to get to this:
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 | % rpmbuild --rebuild python25-2.5.1-bashton1.src.rpm 2>&1 | grep "is needed" | sed 's/^[ \t]\+//g' | awk '{print $1}' readline-devel openssl-devel gmp-devel ncurses-devel gdbm-devel zlib-devel expat-devel libGL-devel tk tix gcc-c++ libX11-devel glibc-devel pkgconfig tcl-devel tk-devel tix-devel bzip2-devel sqlite-devel autoconf db4-devel tcl |
The magic
The real magic and the reason I’m taking the time to write this post up is this little bit of sed magic here:
1 2 | % rpmbuild --rebuild python25-2.5.1-bashton1.src.rpm 2>&1 | grep "is needed" | sed 's/^[ \t]\+//g'| awk '{print $1}' | sed -e :a -e '$!N;s/\n/ /;ta' readline-devel openssl-devel gmp-devel ncurses-devel gdbm-devel zlib-devel expat-devel libGL-devel tk tix gcc-c++ libX11-devel glibc-devel pkgconfig tcl-devel tk-devel tix-devel bzip2-devel sqlite-devel autoconf db4-devel tcl |
This little gem sed -e :a -e ‘$!N;s/\n/ /;ta’ takes all the lines coming in and joins them into a single line.
The final product …
Now you can wrap this command with a yum install `…` like this, and let the power of the shell do all the dirty work for you.
1 | yum -y install `rpmbuild --rebuild python25-2.5.1-bashton1.src.rpm 2>&1 | grep "is needed" | sed 's/^[ \t]\+//g' | awk '{print $1}' | sed -e :a -e '$!N;s/\n/ /;ta'` |
NOTE: For further details regarding my one-liner blog posts, check out my one-liner style guide primer.
March 4th, 2009, @ 12:47 am |
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