Write a shell script to exchange the values of two variables that are related
Unix shell program to swap two numbers without using third variable
The exit status of both of these constructs is the exit status of list. Special parameter 0 is unchanged. GNU Parallel, as its name suggests, can be used to build and run commands in parallel. The wait builtin command may be used to wait for the coprocess to terminate. This pipe is established before any redirections specified by the command see Redirections. The body of the function is the compound command compound-command see Compound Commands. If test2 modifies the variables, the modifications will never be seen in the present script! It is not uncommon to take a list of filenames, create a series of shell commands to operate on them, and feed that list of commands to a shell. Expressions may be combined using the following operators, listed in decreasing order of precedence: expression Returns the value of expression. For instance, a local variable declared in a function hides a global variable of the same name: references and assignments refer to the local variable, leaving the global variable unmodified. Note that for historical reasons, in the most common usage the curly braces that surround the body of the function must be separated from the body by blanks or newlines.
If the assignment precedes a utility name in a command, the export attribute shall not persist in the current execution environment after the utility completes, with the exception that preceding one of the special built-in utilities causes the export attribute to persist after the built-in has completed.
For a complete description, refer to the GNU Parallel documentation.
Special parameter 0 is unchanged. Functions may be recursive. If a variable at the current local scope is unset, it will remain so until it is reset in that scope or until the function returns.
If the date options are used to narrow the scope of files to process, we use the date and an if-statement, to compare whether the modification time of the file is within the specified interval.
The standard input of command is connected via a pipe to a file descriptor in the executing shell, and that file descriptor is assigned to NAME.
Count the number of lines in a given list of files.
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