Here’s some things you should start most bash scripts with:<\/p>\n
#!\/bin\/bash\r\n\r\nset -e\r\nset -x\r\nset -o pipefail\r\nset -u\r\n\r\n\r\nTMPDIR=$(mktemp -d)\r\ntrap 'rm -rf $TMPDIR' EXIT\r\n<\/pre>\nExplanations of the lines:<\/p>\n
#!\/bin\/bash<\/pre>\nThe shebang line is a unix convention that allows scripts to specify their interpreter. Since this is a bash script, we tell it to run this file with bash.<\/p>\n
set -e<\/pre>\nExit immediately if any command fails. Makes it easy to spot when a script did not complete, and prevents things further down the line from doing the wrong thing because they were only partially setup.<\/p>\n
set -x<\/pre>\nPrint each command as it’s run. It’s fantastically useful debug output, though some production scripts should have this disabled.<\/p>\n
set -o pipefail<\/pre>\nExit with failure if any substage of a pipeline fails. This is about commands chained together with a pipe; e.g. If your grep command fails, the execution will fail, rather than simply outputting nothing to the next stage of the pipeline.<\/p>\n
set -u<\/pre>\nMakes referencing unset variables an error. <\/p>\n
Further explaination of the above three can be found in the Bash Reference Manual entry on Set<\/a>.<\/p>\n
TMPDIR=$(mktemp -d)\r\ntrap 'rm -rf $TMPDIR' EXIT<\/pre>\nCreate a scratch dir, automatically delete it when you’re done. It’s often useful to comment out the trap line during debugging. <\/p>\n
See also Pixelbeat’s blog on Common shell script mistakes<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"
Here’s some things you should start most bash scripts with: #!\/bin\/bash set -e set -x set -o pipefail set -u TMPDIR=$(mktemp -d) trap ‘rm -rf $TMPDIR’ EXIT Explanations of the lines: #!\/bin\/bash The shebang line is a unix convention that allows scripts to specify their interpreter. Since this is a bash script, we tell it … Continue reading Bash tips.<\/span>