printf -vl "%${COLUMNS:-`tput cols 2>&-||echo 80`}s\n" && echo ${l// /-};

Print a row of characters the width of terminal

Unlike other methods that use pipes and exec software like tr or sed or subshells, this is an extremely fast way to print a line and will always be able to detect the terminal width or else defaults to 80. It uses bash builtins for printf and echo and works with printf that supports the non-POSIX `-v` option to store result to var instead of printing to stdout. Here it is in a function that lets you change the line character to use and the length with args, it also supports color escape sequences with the echo -e option. function L() { local l=; builtin printf -vl "%${2:-${COLUMNS:-`tput cols 2>&-||echo 80`}}s\n" && echo -e "${l// /${1:-=}}"; } With color: L "`tput setaf 3`=" 1. Use printf to store n space chars followed by a newline to an environment variable "l" where n is local environment variable from $COLUMNS if set, else it will use `tput cols` and if that fails it will default to 80. 2. If printf succeeds then echo `$l` that contains the chars, replacing all blank spaces with "-" (can be changed to anything you want). From:
Sample Output
$ L '<' 40

$ L '=';

$ L 'x';

$ L '-';

$ L '~';

$ L '`';

$ L '>';

$ L '#';

$ L '@';

These Might Interest You

  • Print a row of characters across the terminal. Uses tput to establish the current terminal width, and generates a line of characters just long enough to cross it. In the example '#' is used. It's possible to use a repeating sequence by dividing the columns by the number of characters in the sequence like this: seq -s'~-' 0 $(( $(tput cols) /2 )) | tr -d '[:digit:]' or seq -s'-~?' 0 $(( $(tput cols) /3 )) | tr -d '[:digit:]' You will lose chararacters at the end if the length isn't cleanly divisible. Show Sample Output

    seq -s'#' 0 $(tput cols) | tr -d '[:digit:]'
    jgc · 2010-04-01 09:06:44 0
  • Using the gcalcli interface to google calendar, print the calendar for the next 2 weeks according to the width of the terminal being used. * Remove "--mon" to start week on sunday, * Change 2 for more or less weeks gcalcli --mon --width $((COLUMNS/8)) calm for whole month Show Sample Output

    gcalcli --mon --width $((COLUMNS/8)) calw 2
    jaw42 · 2013-07-04 12:28:51 0
  • Pure Bash This will print a row of characters the width of the screen without using any external executables. In some cases, COLUMNS may not be set. Here is an alternative that uses tput to generate a default if that's the case. And it still avoids using tr. printf -v row "%${COLUMNS:-$(tput cols)}s"; echo ${row// /#} The only disadvantage to either one is that they create a variable. Show Sample Output

    printf -v row "%${COLUMNS}s"; echo ${row// /#}
    dennisw · 2010-04-13 21:56:46 0
  • Use tput cols to find the width of the terminal and set it as the minimum field width. Show Sample Output

    printf "%$(tput cols)s\n"|tr ' ' '='
    webstandardcss · 2012-04-21 23:26:55 1
  • This command displays a clock on your terminal which updates the time every second. Press Ctrl-C to exit. A couple of variants: A little bit bigger text: watch -t -n1 "date +%T|figlet -f big" You can try other figlet fonts, too. Big sideways characters: watch -n 1 -t '/usr/games/banner -w 30 $(date +%M:%S)' This requires a particular version of banner and a 40-line terminal or you can adjust the width ("30" here). Show Sample Output

    watch -t -n1 "date +%T|figlet"
    dennisw · 2009-06-21 01:02:37 9
  • Per default, linux/unix shells are configured with a width of 80 characters. If you like to edit a phrase or string on a line with more than 80 characters it might take long to go there (for example a line with 1000 characters and you like to edit the 98th word which is character 598-603). Maybe you might wish to use 78 characters, because if you forward the text via mail and the text will be quoted (2 extra characters at the beginning to the line "> "), you use 80 characters, otherwise 82, which are lame.

    fold -w 78 -s file-to-wrap
    GeckoDH · 2009-05-19 19:33:10 1

What do you think?

Any thoughts on this command? Does it work on your machine? Can you do the same thing with only 14 characters?

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