|  |  5.1.128 read 
See
 execute;
 getdump;
 link;
 status;
 write.Syntax:read (link_expression)for DBM links:
 
 read (link_expression)
 read (link_expression,string_expression)Type:any
Purpose:reads data from a link.
For ASCII links, the content of the entire
file is returned as a string. If the ASCII link is the empty string,
 readreads from standard input.For ssi links, one expression is read
from the link and returned after evaluation. See  Ssi links.
 For ssi links the
 readcommand blocks as long as there is no
data to be read from the link. Thestatuscommand can be used to
check whether or not there is data to be read.For DBM links, a
 readwith one argument returns the value of
the next entry in the data base, and areadwith two arguments
returns the value to the key given as the second argument from the data
base. See  DBM links.Example:|  |   ring r=32003,(x,y,z),dp;
  ideal i=x+y,z3+22y;
  // write the ideal i to the file save_i
  write(":w save_i",i);
  ring r0=0,(x,y,z),Dp;
  // create an ideal k equal to the content
  // of the file save_i
  string s="ideal k="+read("save_i")+";";
  execute(s);
  k;
==> k[1]=x+y
==> k[2]=z3+22y
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