bash，关于如何使 bash 脚本的变量可用于另一个 bash 脚本的良好实践？

Question

众所周知，通过将多个脚本使用的公共变量存储在一个公共文件中，可以使它们彼此可用。

与通过保存在 RAM 中的变量进行的交换相比，多个脚本之间通过硬盘上的文件交换变量值会导致相应硬盘上的频繁写入操作。

已知方式的软件实现：

# write a var to a file
echo "var_01=Alfa" > var_file.sh

# set a new value to a var
sed -i 's/var_01=Alfa/var_01=Berta/' var_file.sh

# delete the value of a var and the var
sed -i 's/var_01=Alfa/""/' var_file.sh

# make a var readable to a script by Include var_file.sh
source ./var_file.sh

什么是更好的做法，如何使 bash 脚本的变量可用于另一个 bash 脚本？

备注： 搜索的是：

• 一种通过多个 bash 脚本使用 variales 的方法，无需为需要在文件中存储 var 实际值的 vars 提供帮助文件。它可以在 RAM、pe 上进行。通过非变量类型，可能是全局变量或环境变量等。

Answer 1

使用 bash，使用 declare 关键字可靠地（正确引用或转义特殊字符）将变量保存到文件，即使它包含空格或任何特殊字符。

最终，您可以将save_vars 函数合并到您与所有其他脚本共享的var_file.sh 中，以保存和恢复/共享变量。

var_file.sh

#!/usr/bin/env bash

# Check file is sourced from a bash script or exit with error
if [ -z "$BASH_VERSION" ] || ! (return 0 2>/dev/null); then
  printf 'This %s file is meant to be sourced by a Bash Script\n' "$0" >&2
  exit 1
fi

# Function to save itself and variable names in arguments
# into the current file
# (here it is var_file.sh but could be whatever it is named)
save_vars() {
  # save variables file
  {
    # Write self shebang and usage error handling
    cat <<'EOF'
#!/usr/bin/env bash

if [ -z "$BASH_VERSION" ] || ! (return 0 2>/dev/null); then
  printf 'This %s file is meant to be sourced by a Bash Script\n' "$0" >&2
  exit 1
fi

EOF

    # Save itself "${FUNCNAME[0]}" is the name of
    # the current function here it is save_vars
    declare -f "${FUNCNAME[0]}"

    # Save variable names passed as arguments
    declare -p "$@"

    # Into itself file (self-modify or update)
  } >"${BASH_SOURCE[0]}" 2>/dev/null
}

script1:

#!/usr/bin/env bash

# load variables or exit with failure
. var_file.sh || exit 1

printf 'Hello I am %s\n' "${BASH_SOURCE[0]}"

# Assign value even with spaces and special chars
var_01=$'Alfa Beta Gamma \317\206'
var_02='Something with
a newline'

# Invoke the save_vars function that was imported
# from var_file.sh to save var_01 and var_02
save_vars var_01 var_02

script2:

#!/usr/bin/env bash

# load variables or exit with failure
. var_file.sh || exit 1

printf 'Hello I am %s\n' "${BASH_SOURCE[0]}"
printf 'var_01 contains: %q\n' "$var_01"
printf 'var_02 contains: %q\n' "$var_02"

# set a new value to a var
var_01='Berta'

# delete var_02
unset var_02

# Invoke the save_vars function that was imported
# from var_file.sh to save var_01 only
# (var_02 does not need to be saved since it is deleted
# it will be removed/gone from the save)
save_vars var_01

script3

#!/usr/bin/env bash

# load variables or exit with failure
. var_file.sh || exit 1

printf 'Hello I am %s\n' "${BASH_SOURCE[0]}"
printf 'var_01 contains: %q\n' "$var_01"
printf 'var_02 contains: %q\n' "$var_02"