如果按下向上/向左箭头键,是否可以在bash脚本中使用箭头键来运行某组命令,如果按下向下/向右箭头键,是否可以运行某个设置？我正试图通过使用箭头键在显示数据时快速切换用户,使用此脚本从中读取数据.
function main() # The main function that controls the execution of all other functions
{
mkdir -p ~/usertmp # Make a new temporary user directory if it doesn't exist
touch ~/last_seen_output.txt # Create the output file if it doesn't exist
cat /dev/null > ~/last_seen_output.txt # Make sure that the output file is empty
gather # Call the "gather" function
total=$((`wc -l ~/usertmp/user_list.txt|awk '{print $1}'`-1)) # Calculate the total amount of lines and subtract 1 from the result
echo Current Time: `date +%s` > ~/last_seen_output.txt # Print the current time to the output file for later reference
echo "" > ~/last_seen_output.txt # Print a blank line to the output file
if [ $log -eq 1 ]
then
# If it is enabled, then delete the old backups to prevent errors
while [ $line_number -le $total ]
do
line_number=$((line_number+1)) # Add 1 to the current line number
calculate # Call the "calculate" function
hms # Call the "hms" function to convert the time in seconds to normal time
log
done
else
while [ $line_number -le $total ]
do
line_number=$((line_number+1)) # Add 1 to the current line number
calculate # Call the "calculate" function
hms # Call the "hms" function to convert the time in seconds to normal time
echo "Displaying, please hit enter to view the users one by one."
read # Wait for user input
if [ "$log_while_displaying" ]
then
log
display
else
display
fi
done
fi
}
https://github.com/jbondhus/last-seen/blob/master/last-seen.sh是完整的脚本.
读取命令注释为"等待用户输入"是您输入以转到下一个用户的命令.基本上,这个脚本的用途是列出用户以及自每个用户登录以来所经过的时间.我正在尝试使用箭头键在显示的每个用户之间切换.我认为可以使用case语句来表示键输入.重申我的观点,我不确定这是否可行.如果不是,有人能想到另一种方法吗？
eMP*_*584 15
如前所述,光标键生成三个字节 - 像home/end这样的键甚至生成四个字节!我在某处看到的解决方案是让初始的one-char read()跟随三个后续的one-char读取,并且超时很短.最常见的键序列可以像这样显示:
#!/bin/bash
for term in vt100 linux screen xterm
{ echo "$term:"
infocmp -L1 $term|egrep 'key_(left|right|up|down|home|end)'
}
此外,/ etc/inputrc包含一些带有readline映射的..所以,回答原始问题,这里是来自该bash菜单的剪辑我只是在骇客:
while read -sN1 key # 1 char (not delimiter), silent
do
# catch multi-char special key sequences
read -sN1 -t 0.0001 k1
read -sN1 -t 0.0001 k2
read -sN1 -t 0.0001 k3
key+=${k1}${k2}${k3}
case "$key" in
i|j|$'\e[A'|$'\e0A'|$'\e[D'|$'\e0D') # cursor up, left: previous item
((cur > 1)) && ((cur--));;
k|l|$'\e[B'|$'\e0B'|$'\e[C'|$'\e0C') # cursor down, right: next item
((cur < $#-1)) && ((cur++));;
$'\e[1~'|$'\e0H'|$'\e[H') # home: first item
cur=0;;
$'\e[4~'|$'\e0F'|$'\e[F') # end: last item
((cur=$#-1));;
' ') # space: mark/unmark item
array_contains ${cur} "${sel[@]}" && \
sel=($(array_remove $cur "${sel[@]}")) \
|| sel+=($cur);;
q|'') # q, carriage return: quit
echo "${sel[@]}" && return;;
esac
draw_menu $cur "${#sel[@]}" "${sel[@]}" "$@" >/dev/tty
cursor_up $#
done
小智 8
# This will bind the arrow keys
while true
do
read -r -sn1 t
case $t in
A) echo up ;;
B) echo down ;;
C) echo right ;;
D) echo left ;;
esac
done
您可以使用read -n 1读取一个字符,然后使用case语句根据键选择要执行的操作.
问题是箭头键输出多个字符,序列(及其长度)因终端而异.
例如,在我正在使用的终端上,右箭头输出^[[C.按Ctrl- 可以查看终端输出的顺序V Right Arrow.对于其他光标控制键,例如Page Up和,也是如此End.
相反,我建议使用像<和的单字符键>.在脚本中处理它们会简单得多.
read -n 1 key
case "$key" in
'<') go_left;;
'>') go_right;;
esac
不确定这是否直接回答了问题,但我认为这是相关的 - 我在这些代码来自哪里徘徊,我终于找到了:
起初读起来有点困难; 对于左箭头,在"Key"列中查找"LEFT 4",对于查看的序列bash,查找第5个("keymap" - "normal")列,其中写为"[D 1b 5b 44" - 表示该密钥的三个字节(27,91,68).
查找线程如何读取真正老bash上的箭头键？- UNIX和Linux论坛,激励我编写一个简短的单行代码,它会转储按下的键的密钥代码.基本上,你按一个键,然后按Enter键(触发结束read),然后hexdump用来输出read保存的内容(最后点击Ctrl-C退出循环):
$ while true; do read -p?; echo -n $REPLY | hexdump -C; done
?^[[D
00000000 1b 5b 44 |.[D| # left arrow
00000003
?^[[C
00000000 1b 5b 43 |.[C| # right arrow
00000003
?^[[1;2D
00000000 1b 5b 31 3b 32 44 |.[1;2D| # Shift+left arrow
00000006
?^[[1;2C
00000000 1b 5b 31 3b 32 43 |.[1;2C| # Shift+right arrow
00000006
?^C
因此,虽然箭头键需要3个字节 - Shift +箭头键需要6个!但是,看起来所有这些序列都以0x1b(27)开头,因此可以read -n1在读取更多字节之前检查此值; 还5b保留在多字节序列的"正常"和"移/ NUM锁"上面的表中的列的第二个字节.
编辑:更简单,更正确的方法来扫描Linux中按键的终端代码是通过showkey:
$ showkey
Couldn't get a file descriptor referring to the console
$ showkey -h
showkey version 1.15
usage: showkey [options...]
valid options are:
-h --help display this help text
-a --ascii display the decimal/octal/hex values of the keys
-s --scancodes display only the raw scan-codes
-k --keycodes display only the interpreted keycodes (default)
$ sudo showkey -a
Press any keys - Ctrl-D will terminate this program
^[[A 27 0033 0x1b
91 0133 0x5b
65 0101 0x41
^[[B 27 0033 0x1b
91 0133 0x5b
66 0102 0x42
^[[A 27 0033 0x1b
91 0133 0x5b
65 0101 0x41
^[[D 27 0033 0x1b
91 0133 0x5b
68 0104 0x44
^[[C 27 0033 0x1b
91 0133 0x5b
67 0103 0x43
^C 3 0003 0x03
^M 13 0015 0x0d
^D 4 0004 0x04
您可以在没有任何异常命令的情况下读取箭头键和其他键; 你只需要两个read电话而不是一个电话:
escape_char=$(printf "\u1b")
read -rsn1 mode # get 1 character
if [[ $mode == $escape_char ]]; then
read -rsn2 mode # read 2 more chars
fi
case $mode in
'q') echo QUITTING ; exit ;;
'[A') echo UP ;;
'[B') echo DN ;;
'[D') echo LEFT ;;
'[C') echo RIGHT ;;
*) >&2 echo 'ERR bad input'; return ;;
esac
使用eMPee584答案，我想我为您提出了一个很好的解决方案。它的输出与user3229933answer非常相似，但不会被 shift 键触发，并且可以在大多数终端中使用。
它有 UP DOWN LEFT RIGHT HOME 和 END 键按“q”退出大部分这要归功于 eMPee584
如果您收到类似illegal option n.
#!/bin/bash
while read -sn1 key # 1 char (not delimiter), silent
do
read -sn1 -t 0.0001 k1 # This grabs all three symbols
read -sn1 -t 0.0001 k2 # and puts them together
read -sn1 -t 0.0001 k3 # so you can case their entire input.
key+=${k1}${k2}${k3}
case "$key" in
$'\e[A'|$'\e0A') # up arrow
((cur > 1)) && ((cur--))
echo up;;
$'\e[D'|$'\e0D') # left arrow
((cur > 1)) && ((cur--))
echo left;;
$'\e[B'|$'\e0B') # down arrow
((cur < $#-1)) && ((cur++))
echo down;;
$'\e[C'|$'\e0C') # right arrow
((cur < $#-1)) && ((cur++))
echo right;;
$'\e[1~'|$'\e0H'|$'\e[H') # home key:
cur=0
echo home;;
$'\e[4~'|$'\e0F'|$'\e[F') # end key:
((cur=$#-1))
echo end;;
q) # q: quit
echo Bye!
exit;;
esac
done