在 bash 脚本中使用“tr”
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/26945958/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Working with 'tr' in bash script
提问by tilefrae
How can I work with tr '[a-z]' '[A-Z]'in Bash script?
如何tr '[a-z]' '[A-Z]'在 Bash 脚本中使用？
I want save $1to a text file using tr '[a-z]' '[A-Z]'and print to console.
我想使用保存$1到文本文件tr '[a-z]' '[A-Z]'并打印到控制台。
How can I do this?
我怎样才能做到这一点？
#!/bin/bash
echo | tr '[a-z]' '[A-Z]'
exit 0
is not working.
不管用。
采纳答案by Junior Dussouillez
回答by gniourf_gniourf
With Bash≥4, you don't need to trto convert to upper case since you can use parameter expansions: ${var^^}will expand to the uppercase expansion of var.
使用 Bash≥4，您不需要tr转换为大写，因为您可以使用参数扩展：${var^^}将扩展为var.
#!/bin/bash
# Convert first argument to upper case and save in variable upper1
upper1=${1^^}
# print to console:
printf '%s\n' "$upper1"
# and save to file
printf > file.txt '%s\n' "$upper1"
All this is done in pure Bash with no external tools. Also, there are no pipes and subshells needed.
所有这些都是在纯 Bash 中完成的，没有外部工具。此外，不需要管道和子壳。
