Linux bash 退出状态以及如何在 bash 中设置退出状态

date
status=$?
echo "The date command exit status : ${status}"

#!/bin/bash
# set var 
FILE="/etc/hosts"
 
# get host name 
read -p "Enter a hostname : " hostname
 
# try to locate hostname/computer name in $FILE
grep -q -w "${hostname}" "${FILE}"
 
# store exit status of grep
# if found grep will return 0 exit status
# if not found, grep will return a nonzero exit status
status=$?
 
if test $status -eq 0
then
	echo "Host '$hostname' found in $FILE file."
else
	echo "Host '$hostname' not found in $FILE file."
fi

command && echo "success"
command || echo "failed"
command && echo "success" || echo "failed"

#!/bin/Bash
_files="$@"
 
## fail safe ##
[[ "$_files" == "" ]] && { echo "Usage: $0 filexfcolrxrvkjutidsbhbcqexuvunyawhv.png filejgwsanhgqivghcfhomxmruykhukcwiwr.png"; exit 1; }
 
## continue below ##

#!/bin/bash
set -e
I=~/bin/tags.deleted.410
O="/tmp/https.www.example.com.410.url.conf"
t="$1"
[ ! -f "$I" ] && { echo "$I file not found."; exit 10; }
[ "$t" == "" ] && { echo "Usage: $0 number-of-urls-to-purge-from-$I"; exit 11; }
 
>$O
 
cat "$I" | sort | uniq | while read -r u
do
	uu="${u##https://www.example.com}"
	echo "~^$uu 1;" >>"${O}"
done
echo "* Config file created at ${O} ..."
echo "* Installing ${O} file on utls-wp-mg-www ..."
~/bin/install.py "${O}"
echo "* Send config to rest of cluster nodes ... "
~/bin/install.py --sync --cluster --reload cbz-www
echo "* Building list purge urls for Cloudflare CDN ..."
sleep 1
url=""
while IFS= read -r u
do
        url="$url $u"
done <<<"$(tail -${t} ${I})"
[ "$url" != "" ] && ~/bin/cloudflare.purge.urls.sh "$url"
[ -f "$O" ] && rm -f "$O"