根据开源社区学bash- rustup.sh
dg-publish: true
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs -o rustup.sh
${TERM+SET}可以判断TERM这个变量是否有被赋值,如果有被赋值,则结果为set,否者为空
local _ansi_escapes_are_valid=false
if [ -t 2 ]; then
if [ "${TERM+set}" = 'set' ]; then
case "$TERM" in
xterm*|rxvt*|urxvt*|linux*|vt*)
_ansi_escapes_are_valid=true
;;
esac
fi
fi
对于一个命令是否存在一般使用command -v来判断
say() {
printf 'rustup: %s\n' "$1"
}
err() {
say "$1" >&2
exit 1
}
need_cmd() {
if ! check_cmd "$1"; then
err "need '$1' (command not found)"
fi
}
check_cmd() {
command -v "$1" > /dev/null 2>&1
}
assert_nz() {
if [ -z "$1" ]; then err "assert_nz $2"; fi
}
# Run a command that should never fail. If the command fails execution
# will immediately terminate with an error showing the failing
# command.
ensure() {
if ! "$@"; then err "command failed: $*"; fi
}
# This is just for indicating that commands' results are being
# intentionally ignored. Usually, because it's being executed
# as part of error handling.
ignore() {
"$@"
}