[英]When/how to use “==” or “-eq” operator in test?
In the following code I want to compare the command line arguments with the parameters but I am not sure what is the current syntax to compare the arguments with parameters..ie "==" or "-eq". 在下面的代码中,我想比较命令行参数和参数,但我不确定将参数与parameters..ie“==”或“-eq”进行比较的当前语法是什么。
#!/bin/bash
argLength=$#
#echo "arg = $1"
if [ argLength==0 ]; then
#Running for the very first
#Get the connected device ids and save it in an array
N=0
CONNECTED_DEVICES=$(adb devices | grep -o '\b[A-Za-z0-9]\{8,\}\b'|sed -n '2,$p')
NO_OF_DEVICES=$(echo "$CONNECTED_DEVICES" | wc -l)
for CONNECTED_DEVICE in $CONNECTED_DEVICES ; do
DEVICE_IDS[$N]="$CONNECTED_DEVICE"
echo "DEVICE_IDS[$N]= $CONNECTED_DEVICE"
let "N= $N + 1"
done
for SEND_DEVICE_ID in ${DEVICE_IDS[@]} ; do
callCloneBuildInstall $SEND_DEVICE_ID
done
elif [ "$1" -eq -b ]; then
if [ $5 -eq pass ]; then
DEVICE_ID=$3
./MonkeyTests.sh -d $DEVICE_ID
else
sleep 1h
callCloneBuildInstall $SEND_DEVICE_ID
fi
elif [ "$1" -eq -m ]; then
echo "Check for CloneBuildInstall"
if [ "$5" -eq pass ]; then
DEVICE_ID=$3
callCloneBuildInstall $SEND_DEVICE_ID
else
echo "call CloneBuildInstall"
# Zip log file and save it with deviceId
callCloneBuildInstall $SEND_DEVICE_ID
fi
fi
function callCloneBuildInstall {
./CloneBuildInstall.sh -d $SEND_DEVICE_ID
}
From help test
: 来自
help test
:
[...]
[...]
STRING1 = STRING2 True if the strings are equal.
[...]
[...]
arg1 OP arg2 Arithmetic tests. OP is one of -eq, -ne, -lt, -le, -gt, or -ge.
But in any case, each part of the condition is a separate argument to [
. 但无论如何,条件的每个部分都是
[
。
if [ "$arg" -eq 0 ]; then
if [ "$arg" = 0 ]; then
Why not use something like 为什么不使用像
if [ "$#" -ne 0 ];
if [“$#” - ne 0]; then # number of args should not be zero
那么args的数量不应该是零
echo "USAGE: "回声“用法:”
fi科幻
When/how to use “==” or “-eq” operator in test?
何时/如何在测试中使用“==”或“-eq”运算符?
To put it simply use ==
when doing lexical comparisons aka string comparisons but use -eq
when having numerical comparisons. 简单地说,在进行词法比较(即字符串比较)时使用
==
,但在进行数值比较时使用-eq
。
Other forms of -eq
(equal) are -ne
(not equal), -gt
(greater than), -ge
(greater than or equal), -lt
(lesser than), and -le
(lesser than or equal). 其他形式的
-eq
(相等)是-ne
(不等于), -gt
(大于), - -ge
(大于或等于), -lt
(小于)和-le
(小于或等于)。
Some may also suggest preferring (( ))
. 有些人也可能建议更喜欢
(( ))
。
Examples: 例子:
[[ $string == "something else" ]]
[[ $string != "something else" ]] # (negated)
[[ $num -eq 1 ]]
[[ $num -ge 2 ]]
(( $num == 1 ))
(( $num >= 1 ))
And always use [[ ]]
over [ ]
when you're in Bash since the former skips unnecessary expansions not related to conditional expressions like word splitting and pathname expansion. 当你在Bash中时总是使用
[[ ]]
不是[ ]
,因为前者跳过了与词分裂和路径名扩展等条件表达式无关的不必要的扩展。
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