[fsaintjacques]

Note to all, prepend all your bash script with

"set -o errexit -o nounset -o pipefail"

It'll save you headaches.

[mod]

Can you at least explain what this is doing, outside of saving me headaches?

[Anderkent]

-errexit: exit the script when a command fails -nounset: fail when referencing an unset variable -pipefail: fail when the any command in a pipeline fails, not just the last one

The last option is unfortunately harder to use, since some programs misbehave in pipelines.

[redsymbol]

http://redsymbol.net/articles/unofficial-bash-strict-mode/

[barsonme]

set -o errexit (set -e): exit script when command fails

set -o nounset (set -u): exit script when it tries to use undeclared variables

set -o pipefail: returns error from pipe `|` if any of the commands in the pipe fail (normally just returns an error if the last fails)

[ArchD]

I use the shebang "#!/bin/bash -e".

To get the same effect as the "set -o errexit -o nounset", I think you can use "#!/bin/bash -e -u". (There seems to be no option for pipefail.)

[ploxiln]

The "shebang" treats everything after the binary as a single argument. It only does one argument from the shebang and the file itself as the final argument. So it would run that kinda like

    bash '-e -u' $file

But you can do

    #!/bin/bash -eu

[yrro]

This breaks if your script is sourced by another shell. Best use 'set -eu' at the start instead.

[shawkinaw]

Yep, my thought exactly. My standard bash header is

    #!/bin/bash
    set -eu
    IFS=$'\n\t'

(Wish there was a shorthand version of pipefail, then I'd always use that too.)

[LeoPanthera]

You can save a line by doing #!/bin/bash -eu

[krotton]

Which is no equivalent if the script is executed using "bash script.sh" ;).