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Questions tagged [printf]

The shell builtin command that formats and prints data. Questions that deal with printf command or broadly using printf syntax by programming language (like awk, PHP, perl, C++...)

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1answer
16 views

Printf format error for number

After some greping and seding I manage to get a value from a csv cell and assign it to a variable (DBR). Here come some odd findings echo $DBR echo "$DBR", printf "%f" $DBR output: 9.1 ,.1 : ...
5
votes
1answer
45 views

%c formatted string shows different behaviour in the shell and in C

If i write a very simple line of code in C: printf("Ascii char for %d is %c\n",65,65); It simply prints A, as ascii value of 65 corresponds to character A. But if I use the same code in shell and ...
13
votes
3answers
506 views

Slightly confused about whether printf in the yash shell is a built-in command or not

The yash shell has a printf built-in, according to its manual. However, this is what I see in a yash shell with default configuration: kk@eeyore ~ $ command -v printf /usr/bin/printf kk@eeyore ~ $ ...
0
votes
1answer
40 views

Find + -printf + sort conflict?

I need to pass a list of sorted, quoted FLAC file names to SoX for concatenation but am having trouble getting sort to work the way I expect it to. If I use: find . -maxdepth 1 -type f -iname "*....
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votes
0answers
24 views

Filter output / print one record per event or time period

I've got a custom HID device which prints out exact coordinates of touched points at real time. It is very sensitive & currently printing out the coordinate that's being touched on multiple ...
1
vote
1answer
59 views

What characters need to be escaped when using the printf command?

I want to clarify that I am not talking about how to escape characters on the shell level of interpretation. As far as I can tell, only two character need to be escaped: % and \ To print a literal %,...
8
votes
2answers
410 views

Explanation needed on how I can repeat a character in POSIX shell

The following answer on Stack Overflow, How can I repeat a character in bash? imposes one plausible way of POSIX-ly repeating a single character, as follows. In this example let's use the equal sign ...
1
vote
1answer
77 views

Printf - print repeating minus symbols [duplicate]

how can I use printf to print a row of minus symbols? when I try: printf "-----------\\n" I get: bash: printf: - : invalid option printf: usage: printf [-v var] format [arguments] when I try: ...
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3answers
78 views

print a column with the desire format output [closed]

I have a list of the following data in a file: -0.3476890000000000 0.0743938333333333 -1.0990240000000000 0.0743938333333333 -0.2169100000000000 0.0879397500000000 and I am ...
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votes
2answers
39 views

how to alignment the output of the last fields

the bash script for i in $script_name do echo -en "running the script - $i\t - " exec 3>&1 4>&2 var=$( { time /tmp/scripts/$i 1>&3 2>&4; } 2>&1) # Captures ...
10
votes
2answers
1k views

Why does `printf “%s”` concatenate two following strings together? [duplicate]

$ printf "%s" a b ab$ printf "%s%s" a b ab I have some problem understand the format specifier for printf. If I am correct it is mostly the same as those for strings in the C programming language. ...
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2answers
38 views

Printing a file in columns with arbitrary amount of rows

I have this file: line1 line2 line3 line4 line5 line6 line7 line8 line9 And I want to print it across 3 columns with this structure so that first column has lines 1-2-3, second column has the lines ...
1
vote
1answer
61 views

printf to n column? [duplicate]

This: dots=$(printf "%0.s." {1..10}) prints this: .......... . I'd like to know how to get printf in Bash to print .s up to a specific column position, let's say 30, where the start column will ...
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votes
3answers
739 views

How to remove filename extension from a list of filenames in bash

I am trying to remove the filename extension from a list of files I've generated with the following bash script: #!/bin/bash file_list=$(find . -type f) #assuming that the files are stored in the ...
1
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2answers
47 views

Reconsider spacing of columns

I have a file with the following format 1 1 1 0.02484183 57.2400000 24.6000000 2 1 2 -0.16091000 56.5200000 24.5600000 3 1 1 0.02484183 55.5700000 24....
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2answers
84 views

Using shell 'printf' where the format string is in a variable and doesn't have a fixed number of field placeholders?

I am writing a shell function which makes an external API call via cURL (the external API syntax isn't under my control). I've approached it like this (simplified): #!/bin/sh template_get_entry='...
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3answers
188 views

Use dash in printf

How can I use a dash in printf string? x=xxx printf -v args "-x=%s" "$x" printf "$var" But it gives an error: ./tmp.sh: line 2: printf: -x: invalid option printf: usage: printf [-v var] format [...
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2answers
428 views

printf command in bash [closed]

printf "%50s\n" " I ate 4 eggs" In this example I want to assign 50 from a variable. And How can I use the variable in for loop in bash? Any Idea?
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votes
1answer
154 views

Printf appending fails

I Tried to run the following similar commands in CentOS (12.x): printf "\nhello" "$HOME"/.bashrc printf "\nhello" ${HOME}/.bashrc After execution I display the content of the .bashrc file and see ...
2
votes
3answers
290 views

Printf fails to intepret backslash and exclamation mark

I am writing a java program from terminal using printf and redirecting its output to a .java file but printf fails to interpret the horizontal backslash tab (\t), and when I have an exclamation mark (!...
0
votes
1answer
27 views

Remove all lines in single file NOT matching keywords aligned in first column [closed]

I need to extract a series of lines identified by a keyword in the first column and print them in the same linear order. The file is divided into sections delimited by a line of hyphens or equal ...
5
votes
3answers
2k views

How to prepend a line to all files in a directory?

I have a directory called backup with file extensions *.sql. The thing I want to do is to prepend a line to all sql files in the directory backup. I did echo 'use my_db;' >> backup/*.sql, which ...
0
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3answers
54 views

Aligning the third word with 20 spaces from the beginning of the second word [duplicate]

We have the following file: cat info.txt linux03.sys98.com net16777728 Speed: 1000Mb/s linux03.sys98.com net16777728 Speed: 1000Mb/s linux01.sys98.com net3f0 Speed: 1000Mb/s ...
1
vote
1answer
59 views

printf work-alike wrapper for prefixing and redirecting error messages

I have an error function in my POSIX sh shell code. It essentially looks like error () { printf 'utility: ERROR: ' >&2 printf "$@" >&2 } The second printf makes it so that I ...
2
votes
3answers
1k views

print all files in a folder

let's say ls retunrs file1 file2 dir1 dire2 ..., I want to print you have file1 file2 dir1 dire2 ... in currnent folder. How can I do that? ls | xargs -i echo 'you have {} in current folder' prints ...
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votes
2answers
2k views

printf escape %q string vs variable [duplicate]

I would like to escape path with white space which works fine when I use it directly like this: $ printf '%q' "/path/to/first dir/dir/" /path/to/first\ dir/dir/ When I use a variable instead of ...
1
vote
1answer
227 views

Using printf when string has backslash

I'm trying to both printf and export the variable used for setting PS1 but everything I've tried returns error in printf or puts literal \u in prompt. v='\u\$'; printf "$v"; export PS1="$v" -bash: ...
5
votes
6answers
4k views

Bash: How to generate random float number using $RANDOM

Is it possible to generate real random numbers with a specific precision and in a specific range using the Integer Random Generator $RANDOM? For example how we can generate real number with 4 ...
1
vote
1answer
450 views

How to printf literal characters from/to file in bash?

I want to filter a file by character (for the purpose of removing invalid xml characters which I cannot control the generation of) but I cannot seem to even be able to copy individual characters from ...
0
votes
1answer
47 views

Inconsistent shell behavior involving endline characters [duplicate]

Why does: [ "a" != "$(printf "\na")" ] && echo true || echo false print true while: [ "a" != "$(printf "\n")a" ] && echo true || echo false print false?
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0answers
222 views

I think printf broke my newlines in terminal [duplicate]

After running a bash script, my (gnome-)terminal ended up printing each new line where the last one ended (but on the next row). I think it was printf that broke things, since it works if I replace ...
5
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6answers
1k views

printf, awk … How to format a number with space to the thousands

Is there a simple way to separate a very large number per thousands with printf, awk, sed ? So 10000000000000 become 10 000 000 000 000 Thanks
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2answers
326 views

find, printf and odd behaviour with ssh

So, this works: find /dir/ -type f -printf "%p|%TY-%Tm-%Td|%TH:%TM|%s|%u|%U\n" > /dir/output.txt But this doesn't: ssh -o StrictHostKeyChecking=no "servername" find /dir/ -type f -printf "%p|%TY-...
2
votes
1answer
76 views

Differences in whitespaces between bash script and interactive shell

Please advice why this happens. from a Linux bash shell: ps PID TTY TIME CMD 20406 pts/0 00:00:01 bash 26896 pts/0 00:00:00 ps I run the follwing str="a b c d" printf "%s\n" ` echo ...
6
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2answers
932 views

Repeat a variable with printf

if I use the following command: printf "%.0s┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃\n" {1..3} I get an output like this: ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃...
4
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1answer
1k views

printf and how to add dots “…” between variables and their values

We have the following output cat gh.log machine status ============================================================= connection_ght 400 pach_po 72 timeout 311 ...
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2answers
1k views

Best way to create table-like CLI display in Bash?

I'm working on a Bash script for massive USB flash memory testing (using f3 under the hood). I need to display a table-like interface with multiple columns and cells. Currently I'm using printf with ...
3
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2answers
1k views

How to output in columns using Bash built-in `printf` where source contains colours?

The code is: #!/bin/bash ips[0]='192.168.0.1' ips[1]='192.168.0' ips[2]='255.255.255.256' ips[3]='123.123.123.123.123' ips[4]='a.b.c.d' ips[5]='255.255.255.255' ips[6]='0.0.0.0' ips[7]='192.168.1.1' ...
12
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1answer
1k views

How do I stop Bash from interpreting octal code instead of integer?

I'm writing a a Horoscope RSS script as an intro to Unix/Linux project, and ran into an issue my Professor couldn't fix in the time I was able to stay after class. Since I couldn't figure out how to ...
0
votes
3answers
1k views

How can I echo with escaped spaces?

I want to echo a variable with spaces into a text file. a=a\ b\ c echo $a > /tmp/a The above results in a file with a b c in it. What if I need the file to read a\ b\ c? I've tried printf %q $a ...
6
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4answers
928 views

printf: multibyte characters

When trying to format printf output involving strings containing multi-byte characters, it became clear that printf does not count literal characters but the number of bytes, which makes formatting ...
1
vote
1answer
3k views

Formatting numerical output in bash to have exactly 4 decimal places

I have a command that outputs a number to a log file, and I don't like the way it looks when the number changes the number of decimal places because it ruins the alignment and makes everything look ...
0
votes
1answer
299 views

How to use rename command with printf

As I was trying to fix the episode numbers of a TV series I toyed with the rename function and trying to pass the return from printf as the rename parameters, but could not do it. I tried just about ...
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1answer
479 views

Bash printf formatting not working!

My script is: #!/bin/bash num1=32.55 num2=145.958 printf "%5.2f\n" $num1 printf "%5.2f\n" $num2 The output is: 32.55 145.96 Instead of: 32.55 145.96 What's going on? If it's any help, I'm ...
11
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6answers
2k views

Padding trailing whitespaces in a string with another character

I'd like to output hello world over 20 characters. printf "%-20s :\n\n" 'hello world!!' # Actual output hello world!! : # Wanted output hello world!!========: However, I don't want to ...
5
votes
1answer
1k views

Does printf have an “engineering” notation format for numbers?

Say I have this number: 105000000, in this form I can't easily see how big it is, so using printf at a prompt I try using the "scientific" notation: % printf "%.3E" 105000000 1.050E+08 This is ...
2
votes
3answers
2k views

Accurate timestamping in Bash with printf (not a trivial problem)

Shell: Bash. Goal: obtain time t in milliseconds since some fixed point in time, suitable for timestamping stuff with printf. Condition: the solution must pass the all-in-one-line-of-text test. ...
2
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2answers
1k views

printf in shell script can't do \x%x

where ECHO-VAR produces \xFF\xFF\xFF\x00 ($fb_COLOR15) these work on the command line: CP="`ECHO-VAR`" printf $CP | dd status=none bs=4 count=$(( ( 1360 * 100 ) + 100 )) > /dev/fb0 printf "`ECHO-...
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votes
2answers
2k views

How to align fields with printf

the following syntax print the output1 down echo "$status" output1: component_name : TEZ_CLIENT recovery_enabled : true component_name : WEBHCAT_SERVER recovery_enabled : true ...
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vote
2answers
1k views

Counting files, directories, etc. in given directory and formatting output on screen

Just started a scripting class and could use some help. I am writing a script to inspect the file names of every file and directory in a given directory and accumulate a count of Every file, ...