摘要

1. 插入

   n

   p="${var1}n${var2}"

   echo -e “${p}”

2. 在源代码中插入新行

   p="${var1}

   ${var2}”
   echo “${p}”
   

3. 使用

   $'n'

   （仅bash和zsh）

   p="${var1}"$'n'"${var2}"

   echo “${p}”

细节

1.插入

n

p="${var1}n${var2}"echo -e "${p}"

echo -e

"n"

var="a b c"first_loop=truefor i in $vardo   p="$pn$i" # Append   unset first_loopdoneecho -e "$p"  # Use -e

避免多余的换行符

var="a b c"first_loop=1for i in $vardo   (( $first_loop )) &&  # "((...))" is bash specific   p="$i" ||  # First -> Set   p="$pn$i" # After -> Append   unset first_loopdoneecho -e "$p"  # Use -e

使用功能

embed_newline(){   local p="$1"   shift   for i in "$@"   do      p="$pn$i"         # Append   done   echo -e "$p"          # Use -e}var="a b c"p=$( embed_newline $var )  # Do not use double quotes "$var"echo "$p"

2.在源代码中插入新行

var="a b c"for i in $vardo   p="$p$i"       # New line directly in the source predoneecho "$p" # Double quotes required          # But -e not required

避免多余的换行符

var="a b c"first_loop=1for i in $vardo   (( $first_loop )) &&  # "((...))" is bash specific   p="$i" ||  # First -> Set   p="$p$i"# After -> Append   unset first_loopdoneecho "$p"     # No need -e

使用功能

embed_newline(){   local p="$1"   shift   for i in "$@"   do      p="$p$i"# Append   done   echo "$p"  # No need -e}var="a b c"p=$( embed_newline $var )  # Do not use double quotes "$var"echo "$p"

3.使用

$'n'

（便携式性较低）

bash和zsh解释

$'n'

var="a b c"for i in $vardo   p="$p"$'n'"$i"doneecho "$p" # Double quotes required          # But -e not required

避免多余的换行符

var="a b c"first_loop=1for i in $vardo   (( $first_loop )) &&  # "((...))" is bash specific   p="$i" ||  # First -> Set   p="$p"$'n'"$i"       # After -> Append   unset first_loopdoneecho "$p"     # No need -e

使用功能

embed_newline(){   local p="$1"   shift   for i in "$@"   do      p="$p"$'n'"$i"    # Append   done   echo "$p"  # No need -e}var="a b c"p=$( embed_newline $var )  # Do not use double quotes "$var"echo "$p"

所有输出都相同

abc

特别感谢以下答案的贡献者：kevinf，GordonDavisson，l0b0，Dolda2000和Tripleee。

编辑

• 另请参见BinaryZebra的答案，其中提供了许多详细信息。
• Abhijeet Rastogi的答案和Dimitry的答案说明了如何避免

  for

  上述bash片段中的循环。