Why does my shell script display different output if each command is run individually?

Question

I have the following shell script

#!/bin/sh
keyExists=`stat ~/.ssh/id_rsa &> /dev/null; echo $?`
echo $keyExists

When I run it as ./test.sh or sh test.sh it outputs

0 File: `/home/vagrant/.ssh/id_rsa' Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: fc00h/64512d Inode: 2888560 Links: 1 Access: (0664/-rw-rw-r--) Uid: ( 1000/ vagrant) Gid: ( 1000/ vagrant) Access: 2014-07-23 11:40:33.355848310 -0400 Modify: 2014-07-23 11:40:33.355848310 -0400 Change: 2014-07-23 11:40:33.355848310 -0400 Birth: -

However when I run each command individually on the command line

keyExists=`stat ~/.ssh/id_rsa &> /dev/null; echo $?`
echo $keyExists

I get the output

Why am I seeing this additional output and how do I suppress this additional output when I run the shell script?

Maybe using /bin/sh runs sh instead of bash, or if it's bash, turns off bash4 enhancements? &> is functional only in bash 4 and later. — Jim Garrison
– Jim Garrison, Commented Jul 23, 2014 at 16:12

kev · Accepted Answer · 2014-07-23 16:11:21Z

2

Before testing, make sure your current shell is /bin/sh, not /bin/bash.

As far as I known: &> is a new feature in bash, not in the old sh.

answered Jul 23, 2014 at 16:11

kev

163k49 gold badges286 silver badges282 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

konsolebox · Accepted Answer · 2014-07-23 16:59:06Z

1

Instead of using &>/dev/null do it as >/dev/null 2>&1. This would make your script work even with ancient sh shells. You can also change your header to #!/bin/bash if you indeed have bash. Or see output of which bash to know.

answered Jul 23, 2014 at 16:59

konsolebox

76.3k13 gold badges110 silver badges114 bronze badges

Collectives™ on Stack Overflow

Why does my shell script display different output if each command is run individually?

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related