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Ugh. If I have to write Bash, I try to enforce some level of basic sanity with: set -euo pipefail I've seen way too many scripts catastrophically fail be

Ugh. If I have to write Bash, I try to enforce some level of basic sanity with: set -euo pipefail I've seen way too many scripts catastrophically fail because of unbound variables or one side of a pipe failing and the script continuing anyways, etc.

paulddraper 10y ago
+1 to this. -e Abort at the first failed line -u Abort when undefined variable is used -o pipefail Piped commands return the status of the last failed command, rather than the status of the last command
iamdave 10y ago
You are a wonderful person for doing this. As an ops guy, I tip my hat.
DCoder 10y ago
I use the verbose version for readability: set -o errexit set -o nounset set -o pipefail Some commands need custom error handling, which means turning off -e: set +o errexit ansible-playbook ... if [[ "$?" != "0" ]]; then echo -e "\e[1;31m""Error when executing ansible!""\e[0m" exit 1 fi set -o errexit And if you use -e , you will probably need the default value helper to validate input arguments: # the :- operator means "use the right side value if the left side ($1) is not set" env=${1:-} inventoryFile="${baseDir}/env/${env}/inventory" if [[ -f "${inventoryFile}" ]]; then echo -e "\e[1;31m""Invalid environment specified!""\e[0m" exit 1 fi
- Ded7xSEoPKYNsDd 10y ago
  I feel your first example is better written like this: if ! ansible-playbook ... ; then echo -e "\e[1;31m""Error when executing ansible!""\e[0m" exit 1 fi But generally when I need to work around errexit, I tend to add something like " || true" or " || xyz_failed=true" to the end of the command line instead of turning it off and on again.
user5994461 10y ago
I'm mostly using ansible instead of bash noawadays. Does all the same with more commands and better error handling.
- SteveNuts 10y ago
  Same here, but Ansible forces a basic knowledge of Python if you want to use it really well.

paulddraper 10y ago

+1 to this. -e Abort at the first failed line -u Abort when undefined variable is used -o pipefail Piped commands return the status of the last failed command, rather than the status of the last command

iamdave 10y ago

You are a wonderful person for doing this. As an ops guy, I tip my hat.

DCoder 10y ago

I use the verbose version for readability: set -o errexit set -o nounset set -o pipefail Some commands need custom error handling, which means turning off -e: set +o errexit ansible-playbook ... if [[ "$?" != "0" ]]; then echo -e "\e[1;31m""Error when executing ansible!""\e[0m" exit 1 fi set -o errexit And if you use -e , you will probably need the default value helper to validate input arguments: # the :- operator means "use the right side value if the left side ($1) is not set" env=${1:-} inventoryFile="${baseDir}/env/${env}/inventory" if [[ -f "${inventoryFile}" ]]; then echo -e "\e[1;31m""Invalid environment specified!""\e[0m" exit 1 fi

Ded7xSEoPKYNsDd 10y ago
I feel your first example is better written like this: if ! ansible-playbook ... ; then echo -e "\e[1;31m""Error when executing ansible!""\e[0m" exit 1 fi But generally when I need to work around errexit, I tend to add something like " || true" or " || xyz_failed=true" to the end of the command line instead of turning it off and on again.

user5994461 10y ago

I'm mostly using ansible instead of bash noawadays. Does all the same with more commands and better error handling.

SteveNuts 10y ago
Same here, but Ansible forces a basic knowledge of Python if you want to use it really well.