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Chapter 20: Canned Sequences of Commands
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one. In addition to the standard C escape sequences, a backslash followed by a
space stands for a space. This is useful for displaying a string with spaces at the
beginning or the end, since leading and trailing spaces are otherwise trimmed
from all arguments. To print ‘ and foo = ’, use the command ‘echo \ and foo
= \ ’.
A backslash at the end of text can be used, as in C, to continue the command
onto subsequent lines. For example,
echo This is some text\n\
which is continued\n\
onto several lines.\n
produces the same output as
echo This is some text\n
echo which is continued\n
echo onto several lines.\n
output expression
Print the value of expression and nothing but that value: no newlines, no
‘$nn = ’. The value is not entered in the value history either. See Section 8.1
[Expressions], page 75, for more information on expressions.
output/fmt expression
Print the value of expression in format fmt. You can use the same formats as
for print. See Section 8.4 [Output Formats], page 78, for more information.
printf template, expressions ...
Print the values of one or more expressions under the control of the string
template. To print several values, make expressions be a comma-separated
list of individual expressions, which may be either numbers or pointers. Their
values are printed as specified by template, exactly as a C program would do
by executing the code below:
printf (template, expressions ...);
As in C printf, ordinary characters in template are printed verbatim, while
conversion specification introduced by the ‘%’ character cause subsequent expressions to be evaluated, their values converted and formatted according to
type and style information encoded in the conversion specifications, and then
printed.
For example, you can print two values in hex like this:
printf "foo, bar-foo = 0x%x, 0x%x\n", foo, bar-foo
printf supports all the standard C conversion specifications, including the flags
and modifiers between the ‘%’ character and the conversion letter, with the
following exceptions:
• The argument-ordering modifiers, such as ‘2$’, are not supported.
• The modifier ‘*’ is not supported for specifying precision or width.
• The ‘’’ flag (for separation of digits into groups according to LC_NUMERIC’)
is not supported.
• The type modifiers ‘hh’, ‘j’, ‘t’, and ‘z’ are not supported.
• The conversion letter ‘n’ (as in ‘%n’) is not supported.