I am trying to write a short bash hack that requires piping keystrokes of the F-Keys
basically what I am trying to do is:
(echo "1"; "for x in 1..9; do echo "123<F1>34<F3>"; done; echo "<F1>")|./program
where is the F-key with that #
is this possible? if so can some one point me to the docs, or something
Depending on your terminal, a function-key is just a sequence of characters. You can see what they are with cat:
$ cat
^[OP
^[OQ
^[OR
This is me hitting F1, F2, F3 in sequence. So to echo them into your program, you can just echo those control codes (note the first one there is ctrl-ESC), and you should be all set.
To expand on zigdon's answer, you can use tput to produce the right sequences for your terminal:
f1=$(tput kf1)
f2=$(tput kf2)
# ...
(echo 1; for x in {1..9}; do echo "123${f1}34$f3"; done; echo "$f1") | ./program
The "kf1" and "kf2" names are the terminfo capabilities for the F1 and F2 keys, respectively.
Related
I'm trying to set up my PS1 prompt variable to dynamically choose a color. To do this, I've defined a bunch of local variables with color names:
$ echo $Green
\033[0;32m
but I was hoping to use those in dynamically assigning variables, but I can't figure out how to expand them properly:
> colorstr="\${$color}"
> echo $colorstr
${Green}
I've tried a dozen combinations of eval, echo, and double-quotes, and none seem to work. The logical way (I thought) to expand the variable results in an error:
> colorstr="${$color}"
-bash: ${$color}: bad substitution
(for clarity I've used > instead of $ for the prompt character, but I am using bash)
How can I expand that variable? i.e., somehow get the word "Green" to the value \033[0;32m? And prefereably, have bash or the terminal parse that \033[0;32m as the color green too.
EDIT: I was mis-using ${!x} and eval echo $x previously, so I've accepted those as solutions. For the (perhaps morbidly) curious, the functions and PS1 variable are on this gist: https://gist.github.com/4383597
Using eval is the classic solution, but bash has a better (more easily controlled, less blunderbuss-like) solution:
${!colour}
The Bash (4.1) reference manual says:
If the first character of parameter is an exclamation point (!), a level of variable indirection
is introduced. Bash uses the value of the variable formed from the rest of parameter as
the name of the variable; this variable is then expanded and that value is used in the rest
of the substitution, rather than the value of parameter itself. This is known as indirect
expansion.
For example:
$ Green=$'\033[32;m'
$ echo "$Green" | odx
0x0000: 1B 5B 33 32 3B 6D 0A .[32;m.
0x0007:
$ colour=Green
$ echo $colour
Green
$ echo ${!colour} | odx
0x0000: 1B 5B 33 32 3B 6D 0A .[32;m.
0x0007:
$
(The odx command is very non-standard but simply dumps its data in a hex format with printable characters shown on the right. Since the plain echo didn't show anything and I needed to see what was being echoed, I used an old friend I wrote about 24 years ago.)
Using eval should do it:
green="\033[0;32m"
colorstr="green"
eval echo -e "\$$colorstr" test # -e = enable backslash escapes
test
The last test is in color green.
Bash supports associative arrays. Don't use indirection when you could use a dict. If you don't have associative arrays, upgrade to bash 4, ksh93, or zsh. Apparently mksh is adding them eventually as well, so there should be plenty of choice.
function colorSet {
typeset -a \
clrs=(black red green orange blue magenta cyan grey darkgrey ltred ltgreen yellow ltblue ltmagenta ltcyan white) \
msc=(sgr0 bold dim smul blink rev invis)
typeset x
while ! ${2:+false}; do
case ${1#--} in
setaf|setab)
for x in "${!clrs[#]}"; do
eval "$2"'[${clrs[x]}]=$(tput "${1#--}" "$x")'
done
;;
misc)
for x in "${msc[#]}"; do
eval "$2"'[$x]=$(tput "$x")'
done
;;
*)
return 1
esac
shift 2
done
}
function main {
typeset -A fgColors bgColors miscEscapes
if colorSet --setaf fgColors --setab bgColors --misc miscEscapes; then
if [[ -n ${1:+${fgColors[$1]:+_}} ]]; then
printf '%s%s%s\n' "${fgColors[${1}]}" "this text is ${1}" "${miscEscapes[sgr0]}"
else
printf '%s, %s\n' "${1:-Empty}" 'no such color.' >&2
return 1
fi
else
echo 'Failed setting color arrays.' >&2
return 1
fi
}
main "$#"
Though we're using eval, it's a different type of indirection for a different reason. Note how all the necessary guarantees are made for making this safe.
See also: http://mywiki.wooledge.org/BashFAQ/006
You will want to write an alias to a function. Check out http://tldp.org/LDP/abs/html/functions.html, decent little tutorial and some examples.
EDIT:
Sorry, looks like I misunderstood the issue. First it looks like your using the variables wrong, check out http://www.thegeekstuff.com/2010/07/bash-string-manipulation/. Also, what is invoking this script? Are you adding this to the .bash_profile or is this a script your users can launch? Using export should make the changes take effect right away without needed relog.
var Green="\[\e[32m\]"
var Red="\[\e41m\]"
export PS1="${Green} welcome ${Red} user>"
Your first result shows the problem:
$ echo $Green
\033[0;32m
The variable Green contains an string of a backlash, a zero, a 3, etc..
It was set by: Green="\033[0;32m". As such it is not a color code.
The text inside the variable needs to be interpreted (using echo -e, printf or $'...').
Let me explain with code:
$ Green="\033[0;32m" ; echo " $Green test "
\033[0;32m test
What you mean to do is:
$ Green="$(echo -e "\033[0;32m" )" ; echo " $Green test "
test
In great color green. This could print the color but will not be useful for PS1:
$ Green="\033[0;32m" ; echo -e " $Green test "
test
As it means that the string has to be interpreted by echo -e before it works.
An easier way (in bash) is :
$ Green=$'\033[0;32m' ; echo " $Green test "
test
Please note the ` $'...' `
Having solved the issue of the variable Green, accesing it indirectly by the value of var colorstr is a second problem that could be solved by either:
$ eval echo \$$colorstr testing colors
testing colors
$ echo ${!colorstr} testing colors
testing colors
Note Please do not work with un-quoted values (as I did here because the values were under my control) in general. Learn to quote correctly, like:
$ eval echo \"\$$colorstr testing colors\"
And with that, you could write an PS1 equivalent to:
export PS1="${Green} welcome ${Red} user>"
with:
Green=$'\033[0;32m' Red=$'\033[0;31m'
color1=Green color2=Red
export PS1="${!color1} welcome ${!color2} user>"
I have a bash script which generates a motd. The problem is depending on some terminal settings which I am not sure about the color will extend to the end of the line. Othertimes it doesn't:
e.g.
v.s.
IIRC one is just the normal gnome-terminal and the other is my tmux term. So my question is how can I get this to extend to 80 character (or really to the terminal width). Of course I can pad to 80 chars but that really doesn't solve the problem.
Here is a snip of my code which generates the motd:
TC_RESET="^[[0m"
TC_SKY="^[[0;37;44m"
TC_GRD="^[[0;30;42m"
TC_TEXT="^[[38;5;203m"
echo -n "${TC_SKY}
... lots of printing..."
echo -e "\n Welcome to Mokon's Linux! \n"
echo -n "${TC_GRD}"
nodeinfo # Just prints the info seen below...
echo ${TC_RESET}
How can I programmatically from bash change the terminal settings or something change the color to the end of the line?
Maybe use the Escape sequence to clear-to-EOL
For some reason (on my MacOS terminal!) I only needed specify this sequence and then it worked for all the lines but for completeness I list it for all
TC_RESET=$'\x1B[0m'
TC_SKY=$'\x1B[0;37;44m'
TC_GRD=$'\x1B[0;30;42m'
TC_TEXT=$'\x1B[38;5;203m'
CLREOL=$'\x1B[K'
echo -n "${TC_SKY}${CLREOL}"
echo -e "\n ABC${CLREOL}\n"
echo -e "\n DEFG${CLREOL}\n"
echo -n "${TC_GRD}"
echo -e "\n ABC${CLREOL}\n"
echo -e "\n DEFG${CLREOL}\n"
echo ${TC_RESET}
Padding filter
Unfortunely, you have to pad each line with exact number of spaces for changing the color of the whole line's background.
As you're speaking about bash, my solution will use bashisms (Won't work under other shell, or older version of bash).
syntax printf -v VAR FORM ARGS assign to varianble VAR then result of sprintf FORM ARGS. That's bashism, under other kind of shell, you have to replace this line by TC_SPC=$(printf "%${COLUMNS}s" '')
You may try this:
... lots of printing..."
echo -e "\n Welcome to Mokon's Linux! \n"
echo -n "${TC_GRD}"
printf -v TC_SPC "%${COLUMNS}s" ''
nodeinfo |
sed "s/$/$TC_SPC/;s/^\\(.\\{${COLUMNS}\\}\\) */\\1/" # Just prints the info seen below...
echo ${TC_RESET}
Maybe you have to ensure that $COLUMNS is correctly setted:
COLUMNS=$(tput cols)
As you could see, only the result of command filtered by sed is fully colored.
you may
use same filter many times:
cmd1 | sed '...'
cmd2 | sed '...'
or group your commands to use only one filter:
( cmd1 ; cmd 2 ) | sed '...'
But there is an issue in case you try to filter ouptut that contain formatting escapes:
(
echo $'\e[33;44;1mYellow text on blue background';
seq 1 6;
echo $'\e[0m'
) | sed "
s/$/$TC_SPC/;
s/^\\(.\\{${COLUMNS}\\}\\) */\\1/"
Il the lines you have to pad to contain escapes, you have to isolate thems:
(
echo $'\e[33;44;1mYellow text on blue background';
seq 1 6;
echo $'\e[0m'
) | sed "
s/\$/$TC_SPC/;
s/^\\(\\(\\o33\\[[0-9;]*[a-zA-Z]\\)*\\)\\([^\o033]\\{${COLUMNS}\\}\\) */\\1\\3/
"
And finally to be able to fill terminate very long lines:
(
echo $'\e[33;44;1mYellow text on blue background';
seq 1 6;
echo "This is a very very long long looooooooooong line that contain\
more characters than the line could hold...";
echo $'\e[0m';
) | sed "
s/\$/$TC_SPC/;
s/^\\(\\(\\o33\\[[0-9;]*[a-zA-Z]\\)*\\)\\(\\([^\o033]\\{${COLUMNS}\\}\\)*\\) */\\1\\3/"
Nota: This only work if formating escapes are located at begin of line.
Try with this:
echo -e '\E[33;44m'"yellow text on blue background"; tput sgr0
I'm trying to set up my PS1 prompt variable to dynamically choose a color. To do this, I've defined a bunch of local variables with color names:
$ echo $Green
\033[0;32m
but I was hoping to use those in dynamically assigning variables, but I can't figure out how to expand them properly:
> colorstr="\${$color}"
> echo $colorstr
${Green}
I've tried a dozen combinations of eval, echo, and double-quotes, and none seem to work. The logical way (I thought) to expand the variable results in an error:
> colorstr="${$color}"
-bash: ${$color}: bad substitution
(for clarity I've used > instead of $ for the prompt character, but I am using bash)
How can I expand that variable? i.e., somehow get the word "Green" to the value \033[0;32m? And prefereably, have bash or the terminal parse that \033[0;32m as the color green too.
EDIT: I was mis-using ${!x} and eval echo $x previously, so I've accepted those as solutions. For the (perhaps morbidly) curious, the functions and PS1 variable are on this gist: https://gist.github.com/4383597
Using eval is the classic solution, but bash has a better (more easily controlled, less blunderbuss-like) solution:
${!colour}
The Bash (4.1) reference manual says:
If the first character of parameter is an exclamation point (!), a level of variable indirection
is introduced. Bash uses the value of the variable formed from the rest of parameter as
the name of the variable; this variable is then expanded and that value is used in the rest
of the substitution, rather than the value of parameter itself. This is known as indirect
expansion.
For example:
$ Green=$'\033[32;m'
$ echo "$Green" | odx
0x0000: 1B 5B 33 32 3B 6D 0A .[32;m.
0x0007:
$ colour=Green
$ echo $colour
Green
$ echo ${!colour} | odx
0x0000: 1B 5B 33 32 3B 6D 0A .[32;m.
0x0007:
$
(The odx command is very non-standard but simply dumps its data in a hex format with printable characters shown on the right. Since the plain echo didn't show anything and I needed to see what was being echoed, I used an old friend I wrote about 24 years ago.)
Using eval should do it:
green="\033[0;32m"
colorstr="green"
eval echo -e "\$$colorstr" test # -e = enable backslash escapes
test
The last test is in color green.
Bash supports associative arrays. Don't use indirection when you could use a dict. If you don't have associative arrays, upgrade to bash 4, ksh93, or zsh. Apparently mksh is adding them eventually as well, so there should be plenty of choice.
function colorSet {
typeset -a \
clrs=(black red green orange blue magenta cyan grey darkgrey ltred ltgreen yellow ltblue ltmagenta ltcyan white) \
msc=(sgr0 bold dim smul blink rev invis)
typeset x
while ! ${2:+false}; do
case ${1#--} in
setaf|setab)
for x in "${!clrs[#]}"; do
eval "$2"'[${clrs[x]}]=$(tput "${1#--}" "$x")'
done
;;
misc)
for x in "${msc[#]}"; do
eval "$2"'[$x]=$(tput "$x")'
done
;;
*)
return 1
esac
shift 2
done
}
function main {
typeset -A fgColors bgColors miscEscapes
if colorSet --setaf fgColors --setab bgColors --misc miscEscapes; then
if [[ -n ${1:+${fgColors[$1]:+_}} ]]; then
printf '%s%s%s\n' "${fgColors[${1}]}" "this text is ${1}" "${miscEscapes[sgr0]}"
else
printf '%s, %s\n' "${1:-Empty}" 'no such color.' >&2
return 1
fi
else
echo 'Failed setting color arrays.' >&2
return 1
fi
}
main "$#"
Though we're using eval, it's a different type of indirection for a different reason. Note how all the necessary guarantees are made for making this safe.
See also: http://mywiki.wooledge.org/BashFAQ/006
You will want to write an alias to a function. Check out http://tldp.org/LDP/abs/html/functions.html, decent little tutorial and some examples.
EDIT:
Sorry, looks like I misunderstood the issue. First it looks like your using the variables wrong, check out http://www.thegeekstuff.com/2010/07/bash-string-manipulation/. Also, what is invoking this script? Are you adding this to the .bash_profile or is this a script your users can launch? Using export should make the changes take effect right away without needed relog.
var Green="\[\e[32m\]"
var Red="\[\e41m\]"
export PS1="${Green} welcome ${Red} user>"
Your first result shows the problem:
$ echo $Green
\033[0;32m
The variable Green contains an string of a backlash, a zero, a 3, etc..
It was set by: Green="\033[0;32m". As such it is not a color code.
The text inside the variable needs to be interpreted (using echo -e, printf or $'...').
Let me explain with code:
$ Green="\033[0;32m" ; echo " $Green test "
\033[0;32m test
What you mean to do is:
$ Green="$(echo -e "\033[0;32m" )" ; echo " $Green test "
test
In great color green. This could print the color but will not be useful for PS1:
$ Green="\033[0;32m" ; echo -e " $Green test "
test
As it means that the string has to be interpreted by echo -e before it works.
An easier way (in bash) is :
$ Green=$'\033[0;32m' ; echo " $Green test "
test
Please note the ` $'...' `
Having solved the issue of the variable Green, accesing it indirectly by the value of var colorstr is a second problem that could be solved by either:
$ eval echo \$$colorstr testing colors
testing colors
$ echo ${!colorstr} testing colors
testing colors
Note Please do not work with un-quoted values (as I did here because the values were under my control) in general. Learn to quote correctly, like:
$ eval echo \"\$$colorstr testing colors\"
And with that, you could write an PS1 equivalent to:
export PS1="${Green} welcome ${Red} user>"
with:
Green=$'\033[0;32m' Red=$'\033[0;31m'
color1=Green color2=Red
export PS1="${!color1} welcome ${!color2} user>"
I have one problem.
My text should be aligned by right in specified width. I have managed to cut output to the desired size, but i have problem with putting everything on right side
Here is what i got:
#!/usr/local/bin/bash
length=$1
file=$2
echo $1
echo -e "length = $length \t file = $file "
f=`fold -w$length $file > output`
while read line
do
echo "line is $line"
done < "output"
thanks
Try:
printf "%40.40s\n" "$line"
This will make it right-aligned with width 40. If you want no truncation, drop .40 (thanks Dennis!):
printf "%40s\n" "$line"
For example:
printf "%5.5s\n" abc
printf "%5.5s\n" abcdefghij
printf "%5s\n" abc
printf "%5s\n" abcdefghij
will print:
abc
abcde
abc
abcdefghij
Your final step could be
sed -e :a -e 's/^.\{1,$length\}$/ &/;ta'
This is a very old question (2010) but it's the top google result, so might as well. Of the existing answers here, one is a guess that doesn't adjust for terminal width, and the other one invokes sed which is unnecessarily costly.
The printf solution is better as it's a bash builtin, so it vwon't slow things down, but instead of guessing - bash gives you $COLUMNS to tell you how wide the terminal window you're dealing with is.
so while you can explicitly align to, say the 40th column:
printf "%40s\n" "$the_weather"
You can size it for whatever your terminal width is with:
printf "%$COLUMNSs\n" "$the_weather"
(since we're mixing up syntax here, we have used the full form syntax for a bash variable i.e. ${COLUMNS} instead of $COLUMNS, so that bash can identify the variable from the other syntax
In action .. now that we've freed up all that sed processing time, we can use it for something else maybe:
the_weather="$(curl -sm2 'http://wttr.in/Dublin?format=%l:+%c+%f')"
printf "%${COLUMNS}s\n" "${the_weather:-I hope the weather is nice}"
I've got a script 'myscript' that outputs the following:
abc
def
ghi
in another script, I call:
declare RESULT=$(./myscript)
and $RESULT gets the value
abc def ghi
Is there a way to store the result either with the newlines, or with '\n' character so I can output it with 'echo -e'?
Actually, RESULT contains what you want — to demonstrate:
echo "$RESULT"
What you show is what you get from:
echo $RESULT
As noted in the comments, the difference is that (1) the double-quoted version of the variable (echo "$RESULT") preserves internal spacing of the value exactly as it is represented in the variable — newlines, tabs, multiple blanks and all — whereas (2) the unquoted version (echo $RESULT) replaces each sequence of one or more blanks, tabs and newlines with a single space. Thus (1) preserves the shape of the input variable, whereas (2) creates a potentially very long single line of output with 'words' separated by single spaces (where a 'word' is a sequence of non-whitespace characters; there needn't be any alphanumerics in any of the words).
Another pitfall with this is that command substitution — $() — strips trailing newlines. Probably not always important, but if you really want to preserve exactly what was output, you'll have to use another line and some quoting:
RESULTX="$(./myscript; echo x)"
RESULT="${RESULTX%x}"
This is especially important if you want to handle all possible filenames (to avoid undefined behavior like operating on the wrong file).
In case that you're interested in specific lines, use a result-array:
declare RESULT=($(./myscript)) # (..) = array
echo "First line: ${RESULT[0]}"
echo "Second line: ${RESULT[1]}"
echo "N-th line: ${RESULT[N]}"
In addition to the answer given by #l0b0 I just had the situation where I needed to both keep any trailing newlines output by the script and check the script's return code.
And the problem with l0b0's answer is that the 'echo x' was resetting $? back to zero... so I managed to come up with this very cunning solution:
RESULTX="$(./myscript; echo x$?)"
RETURNCODE=${RESULTX##*x}
RESULT="${RESULTX%x*}"
Parsing multiple output
Introduction
So your myscript output 3 lines, could look like:
myscript() { echo $'abc\ndef\nghi'; }
or
myscript() { local i; for i in abc def ghi ;do echo $i; done ;}
Ok this is a function, not a script (no need of path ./), but output is same
myscript
abc
def
ghi
Considering result code
To check for result code, test function will become:
myscript() { local i;for i in abc def ghi ;do echo $i;done;return $((RANDOM%128));}
1. Storing multiple output in one single variable, showing newlines
Your operation is correct:
RESULT=$(myscript)
About result code, you could add:
RCODE=$?
even in same line:
RESULT=$(myscript) RCODE=$?
Then
echo $RESULT $RCODE
abc def ghi 66
echo "$RESULT"
abc
def
ghi
echo ${RESULT#Q}
$'abc\ndef\nghi'
printf '%q\n' "$RESULT"
$'abc\ndef\nghi'
but for showing variable definition, use declare -p:
declare -p RESULT RCODE
declare -- RESULT="abc
def
ghi"
declare -- RCODE="66"
2. Parsing multiple output in array, using mapfile
Storing answer into myvar variable:
mapfile -t myvar < <(myscript)
echo ${myvar[2]}
ghi
Showing $myvar:
declare -p myvar
declare -a myvar=([0]="abc" [1]="def" [2]="ghi")
Considering result code
In case you have to check for result code, you could:
RESULT=$(myscript) RCODE=$?
mapfile -t myvar <<<"$RESULT"
declare -p myvar RCODE
declare -a myvar=([0]="abc" [1]="def" [2]="ghi")
declare -- RCODE="40"
3. Parsing multiple output by consecutives read in command group
{ read firstline; read secondline; read thirdline;} < <(myscript)
echo $secondline
def
Showing variables:
declare -p firstline secondline thirdline
declare -- firstline="abc"
declare -- secondline="def"
declare -- thirdline="ghi"
I often use:
{ read foo;read foo total use free foo ;} < <(df -k /)
Then
declare -p use free total
declare -- use="843476"
declare -- free="582128"
declare -- total="1515376"
Considering result code
Same prepended step:
RESULT=$(myscript) RCODE=$?
{ read firstline; read secondline; read thirdline;} <<<"$RESULT"
declare -p firstline secondline thirdline RCODE
declare -- firstline="abc"
declare -- secondline="def"
declare -- thirdline="ghi"
declare -- RCODE="50"
After trying most of the solutions here, the easiest thing I found was the obvious - using a temp file. I'm not sure what you want to do with your multiple line output, but you can then deal with it line by line using read. About the only thing you can't really do is easily stick it all in the same variable, but for most practical purposes this is way easier to deal with.
./myscript.sh > /tmp/foo
while read line ; do
echo 'whatever you want to do with $line'
done < /tmp/foo
Quick hack to make it do the requested action:
result=""
./myscript.sh > /tmp/foo
while read line ; do
result="$result$line\n"
done < /tmp/foo
echo -e $result
Note this adds an extra line. If you work on it you can code around it, I'm just too lazy.
EDIT: While this case works perfectly well, people reading this should be aware that you can easily squash your stdin inside the while loop, thus giving you a script that will run one line, clear stdin, and exit. Like ssh will do that I think? I just saw it recently, other code examples here: https://unix.stackexchange.com/questions/24260/reading-lines-from-a-file-with-bash-for-vs-while
One more time! This time with a different filehandle (stdin, stdout, stderr are 0-2, so we can use &3 or higher in bash).
result=""
./test>/tmp/foo
while read line <&3; do
result="$result$line\n"
done 3</tmp/foo
echo -e $result
you can also use mktemp, but this is just a quick code example. Usage for mktemp looks like:
filenamevar=`mktemp /tmp/tempXXXXXX`
./test > $filenamevar
Then use $filenamevar like you would the actual name of a file. Probably doesn't need to be explained here but someone complained in the comments.
How about this, it will read each line to a variable and that can be used subsequently !
say myscript output is redirected to a file called myscript_output
awk '{while ( (getline var < "myscript_output") >0){print var;} close ("myscript_output");}'