最高命令的Bash脚本输出

Question

When I execute command

top -c -b -n | grep XXX > TEST

on Red Hat Linux command line, all the paths and the rest of the stuff from the top command is exported into the TEST file (in one line it wrote more than 100 columns/character, for example).

However, when I add the same command in a script and run it via crontab , the output is every time only until the 81 column/character.

How can I get the full width information in the cron script?

Answer 1

The explanation is in section 1 of man top :

   -w  :Output-width-override as:  -w [ number ]
        In  Batch  mode, when used without an argument top will
        format output using the COLUMNS= and LINES= environment
        variables,  if  set.  Otherwise, width will be fixed at
        the maximum 512  columns.   With  an  argument,  output
        width can be decreased or increased (up to 512) but the
        number of rows is considered unlimited.

        In normal display mode, when used without  an  argument
        top  will  attempt  to format output using the COLUMNS=
        and LINES= environment  variables,  if  set.   With  an
        argument,  output  width  can  only  be  decreased, not
        increased.  Whether using environment variables  or  an
        argument  with -w, when not in Batch mode actual termi‐
        nal dimensions can never be exceeded.

        Note: Without the use of this command-line option, out‐
        put  width is always based on the terminal at which top
        was invoked whether or not in Batch mode.

COLUMNS and LINES are set by your terminal when you start it and when you resize its window.

Answer 2

You could try the following:

COLUMNS=1000 top -c -b -n 1  | grep XXX > TEST

This will ensure that COLUMNS environment variable value is set to a large value.

Courtesy: ServerFault