linux cp command different behavior between cmd line and shell script.

Question

When building gcc-4.8.1, I met a cp command as following:

#!/bin/sh
set -x
fname="cp.sh"
cp -v $fname.{,.bk}

It will occurs error when execute this script:

  <29>pli[1050]@~/workspace/shell*0 > sh cp.sh
  + fname=cp.sh
  + cp -v cp.sh{,.bk}
  cp: missing destination file operand after âcp.sh{,.bk}â
  Try 'cp --help' for more information.
  <30>pli[1051]@~/workspace/shell*0 >

But when type it on cmd line directly, it works well as expected. It is very in comprehensive to me.\n

  <28>pli[1049]@~/workspace/shell*0 > cp -v cp.sh{,.bk}
  cp.sh -> cp.sh.bk
  <29>pli[1050]@~/workspace/shell*0 > ^C

Try using bash instead of sh. I think I've had this issue before, and doing that solved it. — K. S.
– K. S., Commented Jan 13, 2014 at 2:18
Make sure you're building outside of the src folder. I suggest you read through the LFS especially the sections on gcc. — Elliott Frisch
– Elliott Frisch, Commented Jan 13, 2014 at 2:22
Yes. I built gcc follow the steps of LFS 7.4 chapt5, and build mkdir outside of src folder. — Incarnation P. Lee
– Incarnation P. Lee, Commented Jan 13, 2014 at 2:28
If you prefer bash over dash, on Debian you can do dpkg-reconfigure dash and set bash as default shell. Any "performance" benefits using dash are negligible in my opinion. — John B
– John B, Commented Jan 13, 2014 at 5:14

Elliott Frisch · Accepted Answer · 2014-01-13 02:32:18Z

1

You need to build gcc with "bash". On Ubuntu derived distributions "/bin/sh" in not linked to "/bin/bash" (but to "/bin/dash"); this is documented in the Ubuntu wiki here. I would suggest using a "ppa" if possible.

answered Jan 13, 2014 at 2:32

Elliott Frisch

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