Question

在bash脚本中，我想写一些类似的东西：

=====================================
= Doing something in THIS_DIRECTORY =
=====================================

实际上在我的脚本中我使用：

echo "====================================="
echo "= Doing something in $VARIABLE ="
echo "====================================="

仅当$VARIABLE值的长度合适时才有效，否则会出现错位，如下所示：

=====================================
= Doing something in THIS_IS_ANOTHER_DIRECTORY =
=====================================

如何动态更改上下字符串的长度以保持中间行的长度相同？

Answer 1

VARIABLE="foobar"
X="= Doing something in $VARIABLE ="
echo "${X//?/=}"
echo "$X"
echo "${X//?/=}"

输出：

=============================
= Doing something in foobar =
=============================

Answer 2

这可能适合你（GNU sed）：

sed 'h;s/./=/g;H;G' <<<"= Doing something in $VARIABLE ="

编辑：

将模式空间（PS）中的原始字符串复制到保留空间（HS），用=替换PS中的每个字符，然后将PS附加到HS，最后将HS附加到HS PS并打印出PS。

Answer 3

一种方法是计算$ VARIABLE的长度，然后根据它来回显等于（=）。

var=$(echo "= Doing something in ${variable} =")
equal=$(printf "%-"${#var}"s" "=")
echo "${equal// /=}"; echo ${var}; echo "${equal// /=}"

var将包含中间行文字。 ${#var}将返回中间线的长度。

Answer 4

你可以这样做：

writenchar() {
  local length=$1
  local char=$2

  for (( i = 0; i < $length; ++i )); do
    echo -n "$char"
  done
}

您必须计算中间字符串的长度：

declare middleString="= Doing something in ${VARIABLE} ="
declare border=$(writenlchar "${#middleString}" '=')

并回应它：

echo "${border}"
echo "${middleString}"
echo "${border}"

由于它是一个循环，我将结果存储在变量中，因为它会花费更少。如果您不想要，那么代码将如下所示：

writenlchar "${#middleString}" '='
echo ""
echo "${middleString}"
writenlchar "${#middleString}" '='
echo ""

空回声在这里转储换行符。

告诉我它是否有效（我没有测试）。

Answer 5

另一种允许添加着色的方法

#!/bin/bash

function pretty_p {
    # Pretty-print a header
    echo -e "\e[00;32m"
    for i in in $(seq 1 ${#1}); do printf "%s" "=";done;echo
    echo $1
    for i in in $(seq 1 ${#1}); do printf "%s" "=";done
    echo -e "\e[00m"
}


VARIABLE="foobar"
X="= Doing something in $VARIABLE ="

pretty_p "$X"

输出（遗憾的是黑色 - 白色而非酷炫的grenish）：

==============================
= Doing something in foobar =
==============================

Answer 6

您可以将printf与seq一起使用，以扩展到所需的长度。

var="= Doing something in $VARIABLE ="
equals=$(printf "%0.s=" $(seq ${#var}))
printf "$equals\n$var\n$equals\n"

创建一个与另一个相同大小的字符串

6 个答案: