bash 如何查看 set 设置的 option 是 enabled 还是 not enabled？

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3.6.2 Redirecting Output

Redirection of output causes the file whose name results from the expansion of word to be opened for writing on file descriptor n, or the standard output (file descriptor 1) if n is not specified. If the file does not exist it is created; if it does exist it is truncated to zero size.

The general format for redirecting output is:

[n]>[|]word

If the redirection operator is ‘>’, and the noclobber option to the set builtin has been enabled, the redirection will fail if the file whose name results from the expansion of word exists and is a regular file. If the redirection operator is ‘>|’, or the redirection operator is ‘>’ and the noclobber option is not enabled, the redirection is attempted even if the file named by word exists.

怎么查看 noclobber 的状态？

4 条回复 • 2019-09-18 05:16:57 +08:00

james122333

2019-09-18 05:08:15 +08:00

#!/bin/bash

IFS=$'\n'
for i in $(set -o)
do
case $i in noclobber\ *) echo $i ;; esac
done

james122333

2019-09-18 05:14:23 +08:00

写成 function 了

james122333

2019-09-18 05:16:01 +08:00

#!/bin/bash

get_option() {
[[ -z "$1" || $# -gt 1 ]] && { echo "arguments mismatched!" ; return 1 ; }
local IFS=$'\n'
for i in $(set -o)
do
case $i in
$1\ *)
echo $i
return 0
;;
esac
done
echo "option not found - $1!"
return 1
}

get_option noclobber
get_option bash

james122333

2019-09-18 05:16:57 +08:00

阿直接[[ $# -ne 1 ]]就好