If you're viewing or printing a file with lines that are too long to read, you can use a program like fold (43.8) to fold the lines. Or, if there's lots of white space in each line - multiple spaces and/or TABs next to each other - you can use the script at the end of this article. The pushin script replaces series of spaces and/or TABs with a single space, "pushing in" each line as much as it can. It reads from files or standard input and writes to standard output.
Here's an example of lines in a file that aren't too long (we can't print long lines in this book, anyway) but that do have a lot of white space. Imagine how pushin would help with longer lines:
%cat data
resistor 349-4991-02 23 capacitor 385-2981-49 16 diode 405-3951-58 8 %pushin data
resistor 349-4991-02 23 capacitor 385-2981-49 16 diode 405-3951-58 8
Here's the script:
#!/bin/sed -f s/[ ][ ]*/ /g
Inside each pair of brackets, [ ]
,
the sed substitute command has a space and a TAB.
The replacement string is a single space.
That file doesn't use a shell; the kernel
starts sed directly (45.3)
and gives it the script itself as the input file expected with the
-f option.
If your UNIX can't execute files directly with #!
, type
in this version
instead:
exec sed 's/[ ][ ]*/ /g' ${1+"$@"}
It starts a shell, then
exec replaces the shell with sed (45.7).
The ${1+"$@"}
works around a
problem with argument handling (46.7)
in some Bourne shells.
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