Usually when the terminal command exports files, we will use >, >>.
> : overwrite mode
>> : append mode
➜ echo "hello world" > test2.txt
➜ echo "apple" >> test2.txt
Sometimes, however, export files contain some control symbols.
➜ man grep > test3.txt
➜ vim test3.txt
The export file contains ^H. (^H = Backspace)
How to export normal files？
Use the Linux col command. The Linux col command is used to filter control characters.
➜ man grep | col -b > test4.txt
➜ vim test4.txt
linux col syntax
col [-bfhpx] [-l num]
-b : Do not output any backspaces, printing only the last character written to each column position.
-f : Forward half line feeds are permitted (``fine'' mode). Normally characters printed on a half line boundary are printed on the following line.
-h : Do not output multiple spaces instead of tabs (default). -l num Buffer at least num lines in memory. By default, 128 lines are buffered.
-p : Force unknown control sequences to be passed through unchanged. Normally, col will filter out any control sequences from the input other than those recognized and interpreted by itself, which are listed below.
-x : Output multiple spaces instead of tabs.