test

字串或文字的比對
Str1 = str2 | 當str1與str2相同時, 傳回True
Str1 != str2| 當str1與str2不同時, 傳回True
Str1 < Str2 
Str1 <= Str2
Str1 > Str2
Str1 >= Str2
Str     | 當str不是空字符時, 傳回True
-n str  | 當str的長度大於0時, 傳回True
-z str  | 當str的長度是0時, 傳回True
數字(整數) 比對
Int1 -eq int2 |當int1等於int2時, 傳回True
Int1 -ge int2 |當int1大於/等於int2時, 傳回True
Int1 -le int2 |當int1小於/等於int2時, 傳回True
Int1 -gt int2 |當int1大於int2時, 傳回True
Int1 -ne int2 |當int1不等於int2時, 傳回True
Int1 -lt int2 |當int1小於 int2時, 傳回True 
檔案的比對
-e file   | 檔案是否存在
-d file   | 當file是一個目錄時, 傳回 True
-f file   | 當file是一個普通檔案時, 傳回 True
-r file   | 當file是一個可讀檔案時, 傳回 True
-s file   | 當file檔案內容長度大於0時, 傳回 True; 空白內容傳回 False
-w file   | 當file是一個可寫檔案時, 傳回 True
-x file   | 當file是一個可執行檔案時, 傳回 True

File operators list

Operator Returns
-a FILE True if file exists.
-b FILE True if file is block special.
-c FILE True if file is character special.
-d FILE True if file is a directory.
-e FILE True if file exists.
-f FILE True if file exists and is a regular file.
-g FILE True if file is set-group-id.
-h FILE True if file is a symbolic link.
-L FILE True if file is a symbolic link.
-k FILE True if file has its `sticky' bit set.
-p FILE True if file is a named pipe.
-r FILE True if file is readable by you.
-s FILE True if file exists and is not empty.
-S FILE True if file is a socket.
-t FD True if FD is opened on a terminal.
-u FILE True if the file is set-user-id.
-w FILE True if the file is writable by you.
-x FILE True if the file is executable by you.
-O FILE True if the file is effectively owned by you.
-G FILE True if the file is effectively owned by your group.
-N FILE True if the file has been modified since it was last read.
! EXPR Logical not.
EXPR1 && EXPR2 Perform the and operation.
EXPR1 || EXPR2 Perform the or operation.

 

布林變數應用
# Let us Declare Two Boolean Variables
# Set this one to true
jobstatus=true
# Check it 
if [ "$jobstatus" = true ] ; then
	echo 'Okay :)'
else
	echo 'Noop :('
fi
# Double bracket format syntax to test Boolean variables in bash
bool=false
if [[ "$bool" = true ]] ; then
	echo 'Done.'
else
	echo 'Failed.'
fi
更多範例
# 如果前個指令執行有錯誤時,會執行兩個程序
[ ! $? -eq 0 ] && echo "Abort the process!! you can try it agian after you made change." && exit 1

# 或者
[ ! $? -eq 0 ] && {
 echo "Abort the process!! you can try it agian after you made change."
 exit 1
} 

#
if [[ $RETURN_CODE != 0 ]]; then
        echo "Zulip first start database initi failed in \"initialize-database\" exit code $RETURN_CODE. Exiting."
        exit $RETURN_CODE
fi

#
if [[ $TIMEOUT -eq 0 ]]; then
            echo "Could not connect to database server. Exiting."
            unset PGPASSWORD
            exit 1
fi
#
if (($? > 0)); then
            echo "$SECRET_KEY = $SECRET_VAR" >> "$DATA_DIR/zulip-secrets.conf"
            echo "Secret added for \"$SECRET_KEY\"."
fi
#
if test "x$newbranch" = x; then
    newbranch=`git branch -a | grep "*" | cut -d ' ' -f2`
fi

# Check router home directory.
[ -d "$PROD_HOME" ] || {
	echo "Router home directory ($PROD_HOME) not found"
	exit 1
}

# AND
autoBackupConfiguration() {
    if ([ "$AUTO_BACKUP_ENABLED" != "True" ] && [ "$AUTO_BACKUP_ENABLED" != "true" ]); then
        rm -f /etc/cron.d/autobackup
        echo "Auto backup is disabled. Continuing."
        return 0
    fi
}

# OR
if [ "$MANUAL_CONFIGURATION" = "False" ] || [ "$MANUAL_CONFIGURATION" = "false" ]; then
        databaseConfiguration
        secretsConfiguration
        authenticationBackends
        zulipConfiguration
fi

# Die if $f1 or $f2 is missing 
if [ ! -f "$f1"  ] ||  [ ! -f "$f2" ]
then
	echo "Required files are missing."
else
	echo "Let us build SFTP jail."
fi

# multiple AND
if [ -e "$DATA_DIR/.initiated" ] && ([ "$FORCE_FIRST_START_INIT" != "True" ] && [ "$FORCE_FIRST_START_INIT" != "true" ]); then
    echo "First Start Init not needed. Continuing."
    return 0
fi

# one-liner
 [[ -z "$var" ]] && echo "NULL" || echo "NOT NULL"

# Contain a substring
if [[ $var = *pattern1* ]]; then
    echo "Do something"
fi

[[ $1 != *cyberciti.biz/faq/* ]] && { printf "Error: Specify faq url (e.g., http://www.cyberciti.biz/faq/url-1-2-3/)\n"; exit 2; }

if [[ $fullstring == *"$substr"* ]];

# Regex
if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then

head="win00000:hascom_command.ksh : hostname:wintstc, monitor port#:17911"
if [[ $head =~ ^win00000.*$ ]]; then