I have a command which outputs in this format:
A
B
C
D
E
F
G
I
J
etc
I want the output to be in this format
A B C D E F G I J
I tried using ./script | tr "\n" " " but all it does is remove n from the output
How do I get all the output in one line. (Line wrapped)
Edit: I accidentally put in grep while asking the question. I removed
it. My original question still stands.
The grep is superfluous.
This should work:
./script | tr '\n' ' '
It did for me with a command al that lists its arguments one per line:
$ al A B C D E F G H I J
A
B
C
D
E
F
G
H
I
J
$ al A B C D E F G H I J | tr '\n' ' '
A B C D E F G H I J $
As Jonathan Leffler points out, you don't want the grep. The command you're using:
./script | grep tr "\n" " "
doesn't even invoke the tr command; it should search for the pattern "tr" in files named "\n" and " ". Since that's not the output you reported, I suspect you've mistyped the command you're using.
You can do this:
./script | tr '\n' ' '
but (a) it joins all its input into a single line, and (b) it doesn't append a newline to the end of the line. Typically that means your shell prompt will be printed at the end of the line of output.
If you want everything on one line, you can do this:
./script | tr '\n' ' ' ; echo ''
Or, if you want the output wrapped to a reasonable width:
./script | fmt
The fmt command has a number of options to control things like the maximum line length; read its documentation (man fmt or info fmt) for details.
No need to use other programs, why not use Bash to do the job? (-- added in edit)
line=$(./script.sh)
set -- $line
echo "$*"
The set sets command-line options, and one of the (by default) seperators is a "\n". EDIT: This will overwrite any existing command-line arguments, but good coding practice would suggest that you reassigned these to named variables early in the script.
When we use "$*" (note the quotes) it joins them alll together again using the first character of IFS as the glue. By default that is a space.
tr is an unnecessary child process.
By the way, there is a command called script, so be careful of using that name.
If I'm not mistaken, the echo command will automatically remove the newline chars when its argument is given unquoted:
tmp=$(./script.sh)
echo $tmp
results in
A B C D E F G H I J
whereas
tmp=$(./script.sh)
echo "$tmp"
results in
A
B
C
D
E
F
G
H
I
J
If needed, you can re-assign the output of the echo command to another variable:
tmp=$(./script.sh)
tmp2=$(echo $tmp)
The $tmp2 variable will then contain no newlines.
Related
I'm using this to color the output of a script/command:
commandWithOutput | sed -r 's/(pattern)/'"${COLOR_RED}"'\1'"${COLOR_DEFAULT}"'/g'
(This will color all occurences of string "pattern" in the command's output.) And it works fine with traditional commands. However, if the script/command overwrites lines in its output (maybe this has more to do with a terminal/console than just standard output?), e.g.:
Building project X:
CXX Building file XYZ.cpp... [123/1034]
the behavior isn't as expected. My sed will still color the output but the overwriting doesn't work anymore, i.e.:
Building project X:
CXX Building file ABC.cpp... [1/1034]
CXX Building file DEF.cpp... [2/1034]
CXX Building file GHI.cpp... [3/1034]
CXX Building file JKL.cpp... [4/1034]
CXX Building file MNO.cpp... [5/1034]
// and so on...
CXX Building file XYZ.cpp... [123/1034]
Is there a way to color the output of a script/command that overwrites lines?
I've tried several different ideas ... IFS=$'\r' + OP's sed command ... trying to use an intermediate pipe (mkfifo) for processing the output from commandWithOutput ... a few attempts at trying to unbuffer stdout and/or stdin ... but (so far) could only get a awk solution to work, so fwiw ...
NOTE: I'm assuming OP's command is generating a \r when overwriting a line; if this is not the case the OP can try piping their command's output to | od -c to see what character is at the 'end of the line', with the idea being to use said character in place of my \r references (below).
First we'll write a small script to generate some data, (re)printing over the first few lines, and then printing some 'standalone' lines:
$ cat overwrite
#!/usr/bin/bash
for (( i=1 ; i<="${1}" ; i++ ))
do
printf "this is a test ... ${i}\r"
sleep 1
done
printf "\nanother test output \t and a tab\n"
echo "X."
Running the above generates the following output:
$ overwrite 3
this is a test ... 3 << this line is actually printed 3x times with suffixes of '1', '2' and '3'
another test output and a tab
X.
Running this through od shows the \r at the end of the first 3 lines:
$ overwrite 3 | od -c
0000000 t h i s i s a t e s t .
0000020 . . 1 \r t h i s i s a t
0000040 e s t . . . 2 \r t h i s i
0000060 s a t e s t . . . 3 \r \n
0000100 a n o t h e r t e s t o u t
0000120 p u t \t a n d a t a b \n
0000140 X . \n
0000143
We'll now look at one awk solution for recoloring a specific pattern in the output from our overwrite script ...
First we'll define the start and clear/reset variables for our desired color; for this exercise I'm going to use 'red':
$ myred=$(tput setaf 1) # set our highlight color to red
$ myreset=$(tput sgr0) # disable coloring
NOTE: There are a few ways to define these colors (and the disable/reset); I'll leave that up to the reader to pick what works best in their environment.
Here's one awk solution I found that works:
$ overwrite 3 | awk -v ptn="test" -v cstart="${myred}" -v creset="${myreset}" -v RS="[\n\r]" '{ sub(ptn,cstart ptn creset) ; printf $0 RT }'
Where:
-v ptn="test" - we want to recolor all instances of the string test; we'll pass this in as awk variable ptn
-v cstart="${myred}" - assign our highlight color code (red) to our awk variable cstart
-v creset="${myreset}" - assign our color clear/reset code to the awk variable creset
-v RS="[\n\r]" - redefine our input record separator as either \r or \n
sub(ptn,cstart ptn creset) - replace all instances of test with <red> + test + <reset>
printf $0 RT - print our new line; RT allows us to make use of the same RS that was used to parse out this record
Running the above generates:
this is a test ... 3 << this line is actually printed 3x times with suffixes of '1', '2' and '3', and the 'test' string printed in red
another test output and a tab << the 'test' string is printed in red
X.
I am meant to create a Caesar Cypher that takes in a parameter and shifts the code based on that parameter but my code messes up with the Upper Case and lower case.
So, it's meant to be like:
$ echo "I came, I saw, I conquered." | ./caesar.sh
V pnzr, V fnj, V pbadhrerq.
but I get:
V pnzr, V FnJ, V pBADHERrq.
My code is:
#!/bin/sh
if [ -z "$#" ];then
rotation=13;
else
rotation=$((# % 16));
fi
tr $(printf %${rotation}s | tr ' ' '.')\a-zA-Z a-zA-Z
How can I fix this?
You are rotating across the entire double-alphabet, 'a-zA-Z', so 's' maps to 'F':
abcdefghijklmnopqrstuvwxyzABCDEFGHIKLMNOPQRSTUVWXYZ
|------------^
You apparently want to preserve case, so I would recommend that you apply two separate mappings: first, map 'a-z' to 'n-za-m' (or whatever, as appropriate for your input parameter). Then in the second pass, map capitals, 'A-Z' -> 'N-ZA-M'.
A basic adaptation of your scheme that works is:
rotation=$((${1:-13} % 26))
padding=$(printf "%${rotation}s" "" | tr ' ' '\001')
tr "${padding}a-z" "a-za-z" |
tr "${padding}A-Z" "A-ZA-Z"
This uses parameter expansion and arithmetic to determine the rotation.
It uses your basic mechanism for setting the padding, but uses Control-A instead of . as the padding character; you seldom have Control-A in your text.
The actual rotation commands deal with lower case separately from upper case.
With the script contained in a file script.sh, I got:
$ bash script.sh
I came, I saw, I conquered
Can you say SYZYGY after midnight?
V pnzr, V fnj, V pbadhrerq
Pna lbh fnl FLMLTL nsgre zvqavtug?
$ bash script.sh 3
I came, I saw, I conquered, and O, was it ever worthwhile!
Can you say SYZYGY after midnight? ABC...XYZ abc...xyz
L fdph, L vdz, L frqtxhuhg, dqg R, zdv lw hyhu zruwkzkloh!
Fdq brx vdb VBCBJB diwhu plgqljkw? DEF...ABC def...abc
$
The pipeline meant that the first line of input was not pushed through to the second tr command at the end of line.
I am trying to write a program that will print out every line from a file with another line of that file added at the end, basically creating pairs from a portion of each line. If the line is the same, it will do nothing. Also, it must avoid repeating the same pairs. A B is the same as B A
In short
FileInput:
otherstuff A
otherstuff B
otherstuff C
otherstuff D
Output:
A B
A C
A D
B C
B D
C D
I was trying to do this with a BASH script, but was having trouble because I could not get my nested while loops to work. It would read the first line, compare it to each other line, and then stop (Basically only outputting the first 3 lines in the example output above, the outer while loop only ran once).
I also suspect I might be able to do this using MATLAB, so suggestions using that are also welcome.
Here is the bash script that I have thus far. As I said, it is no printing out correctly for me, as the outer loop only runs once.
#READS IN file from terminal
FILE1=$1
#START count at 0
count0=
exec 3<&0
exec 0< $FILE1
while read LINEa; do
while read LINEb; do
eventIDa=$(echo $LINEa | cut -c20-23)
eventIDb=$(echo $LINEb | cut -c20-23)
echo $eventIDa $eventIDb
done
done
Using bash:
#!/bin/bash
[ -f "$1" ] || { echo >&2 "File not found"; exit 1; }
mapfile -t lines < <(cut -c20-23 <"$1" | sort | uniq)
for i in ${!lines[#]}; do
elem1=${lines[$i]}
unset lines[$i]
for elem2 in "${lines[#]}"; do
echo "$elem1" "$elem2"
done
done
This will read a file given as a parameter on the command line, sort and filter out duplicates, and output all combinations. You can modify the parameter to cut to adjust to your particular input file.
Due to the particular way you seem to indent to use cut, your input example above won't work. Instead, use something with the correct line length, such as:
123456789012345678 A
123456789012345678 B
123456789012345678 C
123456789012345678 D
Assuming the otherstuff is not relevant (otherwise you can of course add it later) this should do the trick in Matlab:
combnk({'A' 'B' 'C' 'D'},2)
I am trying to create a fancy welcome message to be displayed when the terminal is opened. I have done it in Java with this code:
public void slowPrint() {
String message = "Welcome, " + System.getProperty("user.name");
try {
for(int i = 0; i < message.length(); i++) {
System.out.print(message.charAt(i));
Thread.sleep(50);
}
} catch(InterruptedException ex) {
ex.printStackTrace();
}
}
Now, I am fairly new to bash but I've managed to make this code:
for i in W e l c o m e , $USER; do
echo -ne $i
sleep 0.05
done
echo !
There are two problems with this code:
I have no idea how to print a plain space after the comma, the output is just Welcome,simon! How can I make it output a space instead?
It, of course, prints $USER as a whole word. I would want it to be character by character, how can I do this?
You could use a standard for loop to achieve the same effect:
MESSAGE="Welcome, $USER"
for (( i=0; i<${#MESSAGE}; i++ )); do
echo -ne "${MESSAGE:$i:1}"
sleep 0.05
done
echo !
The ${MESSAGE:$i:1} syntax takes a substring of 1 from position i in the string. Enclosing that part in quotes ensures that things like spaces and tabs are also printed.
You can specify the space easily enough; enclose it in quotes:
for i in W e l c o m e , ' ' ...
Splitting $USER into separate characters can be done many ways. The way I'd do it is old-fashioned but reliable:
for i in W e l c o m e , ' ' $(sed 's/./& /g' <<< "$USER")
Note that the <<< operation saves a process and a pipe; it redirects standard input of sed so it reads the given string as a line of input.
Or, if you think the user name might contain any spaces or other special characters:
for i in W e l c o m e , ' ' $(sed "s/./'&' /g" <<< "$USER")
(This isn't bullet proof; the value USER="Tam O'Shanter" will cause some grief, and the simple fix for that runs into trouble with USER='Will "O'\''Wisp" Light' instead. ...mutter, mutter, arcane incantations, ...
for i in W e l c o m e , ' ' $(sed "s/./'&' /g; s/'''/\\\\'/g" <<< "$USER")
except that echoes the name with single quotes around everything; grumble, grumble, ... I think I've just worked out why I wouldn't ever both to do this, ... spaces get in the way too ... I'd use the simple first version and tell people not to use blanks or special characters in the value of $USER.)
There might be are ways to do it without invoking a separate process such as sed; see the answer by heuristicus. So, do it that way. But note that it is firmly tied to bash in a way that this answer isn't wholly tied to bash — you can easily replace the <<< notation (which is bash-only) with echo "$USER" | ... instead.
Completely POSIXly portable, i.e. without those pesky bashisms, and no fork to sed:
#!/bin/sh
m="Welcome, $USER!"
while test ${#m} -gt 0; do
r=${m#?}
printf '%s ' "${m%%$r}"
m=$r
sleep 0.05
done
printf '\n'
Note that sleeping for fractions of a second is non-portable.
I have quick question about text parsing, for example:
INPUT="a b c d e f g"
PATTERN="a e g"
INPUT variable should be modified so that PATTERN characters should be removed, so in this example:
OUTPUT="b c d f"
I've tried to use tr -d $x in a for loop counting by 'PATTERN' but I don't know how to pass output for the next loop iteration.
edit:
How if a INPUT and PATTERN variables contain strings instead of single characters???
Where does $x come from? Anyway, you were close:
tr -d "$PATTERN" <<< $INPUT
To assign the result to a variable, just use
OUTPUT=$(tr -d "$PATTERN" <<< $INPUT)
Just note that spaces will be removed, too, because they are part of the $PATTERN.
Pure Bash using parameter substitution:
INPUT="a b c d e f g"
PATTERN="a e g"
for p in $PATTERN; do
INPUT=${INPUT/ $p/}
INPUT=${INPUT/$p /}
done
echo "'$INPUT'"
Result:
'b c d f'