### 5.1.123 read

`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, `read` reads from standard input.
  For ssi links, one expression is read from the link and returned after evaluation. See Ssi links.
  For ssi links the `read` command blocks as long as there is no data to be read from the link. The `status` command can be used to check whether or not there is data to be read.
  For DBM links, a `read` with one argument returns the value of the next entry in the data base, and a `read` with 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

See execute; getdump; link; status; write.

User manual for Singular version 4-0-3, 2016, generated by texi2html.