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The tcsh Equivalent of the test Command

The tcsh does not have a test command, but it supports the same function using expressions. The expression operators that tcsh supports are almost identical to those supported by the C language. These expressions are used mostly in the if and while commands, which are covered later in this chapter in the “Conditional Statements” and “Iteration Statements” sections.

The tcsh expressions support the same kind of operators as the bash and pdksh test command. These are integer, string, file, and logical expressions. The integer operators supported by tcsh expressions are listed in Table 14.6.

Table 14.6. The tcsh expression integer operators.
Operator Meaning
int1 <= int2 Returns True if int1 is less than or equal to int2.
int1 >= int2 Returns True if int1 is greater than or equal to int2.
int1 < int2 Returns True if int1 is less than int2.
int1 > int2 Returns True if int1 is greater than int2.

The string operators that tcsh expressions support are listed in Table 14.7.

Table 14.7. The tcsh expression string operators.
Operator Meaning
str1 == str2 Returns True if str1 is equal to str2.
str1 != str2 Returns True if str1 is not equal to str2.

The file operators that tcsh expressions support are listed in Table 14.8.

Table 14.8. The tcsh expression file operators.
Operator Meaning
-r file Returns True if file is readable.
-w file Returns True if file is writable.
-x file Returns True if file is executable.
-e file Returns True if file exists.
-o file Returns True if file is owned by the current user.
-z file Returns True if file is of size 0.
-f file Returns True if file is a regular file.
-d file Returns True if file is a directory file.

The logical operators that tcsh expressions support are listed in Table 14.9.

Table 14.9. The tcsh expression logical operators.
Operator Meaning
exp1 || exp2 Returns True if exp1 is true or if exp2 is true.
exp1 && exp2 Returns True if exp1 is true and exp2 is true.
! exp Returns True if exp is not true.

Conditional Statements

The bash, pdksh, and tcsh each have two forms of conditional statements. These are the if statement and the case statement. These statements are used to execute different parts of your shell program depending on whether certain conditions are true. As with most statements, the syntax for these statements is slightly different between the different shells.


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