Shell 命令行參數(shù)

在腳本中通過(guò) $1, $2, $3, 引用參數(shù)${10} 時(shí)，參數(shù)必須在大括號(hào)中。

#!/bin/bash

# Call this script with at least 10 parameters, for example
# ./scriptname 1 2 3 4 5 6 7 8 9 10
MINPARAMS=10

echo

echo "The name of this script is \"$0\"."
# Adds ./ for current directory
echo "The name of this script is \"`basename $0`\"."
# Strips out path name info (see 'basename')

echo

if [ -n "$1" ]              # Tested variable is quoted.
then
 echo "Parameter #1 is $1"  # Need quotes to escape #
fi 

if [ -n "$2" ]
then
 echo "Parameter #2 is $2"
fi 

if [ -n "$3" ]
then
 echo "Parameter #3 is $3"
fi 

# ...


if [ -n "${10}" ]  # Parameters > $9 must be enclosed in {brackets}.
then
 echo "Parameter #10 is ${10}"
fi 

echo "-----------------------------------"
echo "All the command-line parameters are: "$*""

if [ $# -lt "$MINPARAMS" ]
then
  echo
  echo "This script needs at least $MINPARAMS command-line arguments!"
fi  

echo

exit 0

腳本的返回狀態(tài)

shell 中使用exit命令來(lái)結(jié)束腳本，就像C程序一樣，也會(huì)有一個(gè)返回值來(lái)給到父進(jìn)程。

每個(gè)命令都會(huì)返回一個(gè)exit狀態(tài)，如果命令執(zhí)行成功，返回0。如果返回一個(gè)非零值，通常情況下都會(huì)認(rèn)為是一個(gè)錯(cuò)誤碼。

當(dāng)一個(gè)腳本不以exit退出時(shí)，就用最后一個(gè)命令的返回碼來(lái)作為腳本的狀態(tài)。

在shell中，使用$？來(lái)讀取最后一個(gè)命令的退出碼。