Bourne Shell Quick Reference Guide:
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Program Format:
Patterns in program can be associated with a statement to perform if an input line matches the pattern. The format is:
pattern { statement }
A missing pattern always matches, and a missing statement prints the current input line.
Patterns:
BEGIN
match before first input line
END
match after last input line
pattern1, pattern2, ..., patternn
match if pattern1, pattern2, or patternn match current input line
pattern1 && pattern2
match if pattern1 and pattern2 match current input line
pattern1 || pattern2
match if pattern1 or pattern2 match current input line
!pattern
match if pattern does not match current input line
/regular-expression/
match if regular-expression matches current input line
relational-expression
match if relational-expression evaluates to true
Flow Control Statements:
break
exit from a for or while loop
continue
execute next for or while loop
delete variable[expression]
delete element expression from array variable
do statement while (expression)
execute statement while expression is true
exit
skip remaining input
for (expression1; expression2; expression3) statement
execute statement while expression2 is true; loop is usually initialized with expression1 and incremented with expression3
for (variable in array) statement
execute statement, setting variable to successive elements in array
if (expression) statement1 [ else statement2 ]
execute statement1 if expression is true, otherwise execute statement2
next
skip rest of the input line
return[expression]
return value of expression
system(command)
execute command and return status
while (expression) statement
execute statement while expression is true
Input/Output Statements:
close(file)
close file
getline
set $0 to next input record; set NF, NR, FNR
getline<file
set $0 to next input from file; set NF
getline var
set var to next input record; set NR, FNR
getline variable<file
set variable to next input record from file
command | getline
pipe output of command into getline
print
print current input record
print expression
print expression; multiple expressions must be separated with a ","
print expression>file
print expression to file; multiple expressions must be separated with a ","
printf format expression
print expression according to C-like format. Multiple expressions must be separated with a ",". Output can also be appended to file using >> or piped to a command using |.
printf format expression>file
print expression to file according to C-like format. Multiple expressions must be separated with a ",". Output can also be appended to file using >> or piped to a command using |.
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