Linux echo - 语法错误：替换错误
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echo - Syntax error: Bad substitution
提问by andrej
A script with a problem:
有问题的脚本：
1 #!/bin/bash
2
3 skl="test"
4 # get length
5 leng=$(expr length $skl)
6 # get desired length
7 leng=$(expr 22 - $leng)
8
9 # get desired string
10 str=$(printf "%${leng}s" "-")
11
12 # replace empty spaces
13 str=$(echo "${str// /-}")
14
15 # output
16 echo "$str obd: $skl $str"
17
but it outputs:
但它输出：
name.sh: 13: Syntax error: Bad substitution
please help, thanks I would be very grateful :)
请帮忙，谢谢我将不胜感激:)
采纳答案by devnull
The following line:
以下行：
str=$(echo "${str// /-}")
is resulting into Syntax error: Bad substitutionbecause you are notexecuting your script using bash. You are either executing your script using shor dashwhich is causing the error.
导致Syntax error: Bad substitution因为您没有使用bash. 您正在使用sh或dash导致错误的脚本执行。
EDIT: In order to fixyour script to enable it to work with shand dashin addition to bash, you could replace the following lines:
编辑：为了修复您的脚本以使其能够与 一起使用sh并且dash除了 之外bash，您可以替换以下几行：
# get desired string
str=$(printf "%${leng}s" "-")
# replace empty spaces
str=$(echo "${str// /-}")
with
和
str=$(printf '=%.0s' $(seq $leng) | tr '=' '-')
回答by anubhava
Take out all unnecessary expr calls, using pure BASH features:
使用纯 BASH 功能删除所有不必要的 expr 调用：
#!/bin/bash
skl="test"
# get length
leng=${#skl}
# get desired length
leng=$((22 - leng))
# get desired string
str=$(printf "%${leng}s" "-")
# replace empty spaces
str=$(echo "${str// /-}")
# output
echo "$str obd: $skl $str"
