Question

WholeWord="Foo bar sells drinks"
for (( character=0; character<${#WholeWord}; character++ )); do
    echo ${WholeWord:$character}
done

打印出来：

Foo bar sells drinks
oo bar sells drinks
o bar sells drinks
bar sells drinks
bar sells drinks
ar sells drinks
r sells drinks
sells drinks
sells drinks
ells drinks
lls drinks
ls drinks
s drinks
drinks
drinks
rinks
inks
nks
ks
s

我不想修剪每个第一个字母的第一个字母，而是想修剪最后一个字母，创建输出如下：

Foo bar sells drinks
Foo bar sells drink
Foo bar sells drin
Foo bar sells dri
etc.

Answer 1

像这样使用负长度作为第二个参数：

echo "$WholeWord"
for (( character=1; character<${#WholeWord}; character++ )); do
   echo "${WholeWord:0: -$character}"
done

Foo bar sells drinks
Foo bar sells drink
Foo bar sells drin
Foo bar sells dri
Foo bar sells dr
Foo bar sells d
Foo bar sells
Foo bar sells
Foo bar sell
Foo bar sel
Foo bar se
Foo bar s
Foo bar
Foo bar
Foo ba
Foo b
Foo
Foo
Fo
F

Answer 2

几乎所有shell都使用此脚本每次打印后，只需将字符串中的一个字符串切掉：

-f

或者，如果你必须使用#!/bin/sh WholeWord="Foo bar sells drinks" foo="$WholeWord" while [ "$foo" ]; do printf '%s\n' "$foo" foo="${foo%?}" done，那么每一步的长度都会降到1：

Substring Expansion

WholeWord="Foo bar sells drinks"

for (( character=${#WholeWord}; character>0; character-- )); do
    printf '%s\n' "${WholeWord:0:$character}"
done

Answer 3

#!/bin/bash

WholeWord="Foo bar sells drinks"
for (( character=${#WholeWord}; character>0; --character )); do
    echo ${WholeWord:0:$character}
done

此代码的作用：

从整个字符串的大小向后计数到0，从字符串的开头给出该字符数。

Answer 4

不计算字符

$ foo="Foo bar sells drinks"
$ while [[ ! -z $foo ]]; do echo $foo; foo=$(sed 's/.$//' <<< $foo); done

Foo bar sells drinks
Foo bar sells drink
Foo bar sells drin
Foo bar sells dri
Foo bar sells dr
Foo bar sells d
Foo bar sells
Foo bar sell
Foo bar sel
Foo bar se
Foo bar s
Foo bar
Foo ba
Foo b
Foo
Fo
F

for循环：逐步截断右侧的字符串

4 个答案: