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echo "anything" | { grep e || true; }

Explanation:

$ echo "anything" | grep e
### error
$ echo $?
1

$ echo "anything" | { grep e || true; }
### no error
$ echo $?
0

### DopeGhoti's "no-op" version
### (Potentially avoids spawning a process, if `true` is not a builtin):
$ echo "anything" | { grep e || :; }
### no error
$ echo $?
0

The || means "or". If the first part of the command "fails" (meaning grep e returns a non-zero exit code) then the part after the || is executed, succeeds and returns zero as the exit code (true always returns zero).

echo "anything" | { grep e || true; }

Explanation:

• This will throw an error

  $ echo "anything" | grep e
  $ echo $?
  1
  

• This will not throw an error

  $ echo "anything" | { grep e || true; }
  $ echo $?
  0
  

• DopeGhoti's "no-op" version (Potentially avoids spawning a process, if true is not a builtin), this will not throw an error

  $ echo "anything" | { grep e || :; }
  $ echo $?
  0
  

The || means "or". If the first part of the command "fails" (meaning grep e returns a non-zero exit code) then the part after the || is executed, succeeds and returns zero as the exit code (true always returns zero).

echo "anything" | { grep e || true; }

Explanation:

$ echo "anything" | grep e
### error
$ echo $?
1
$ echo "anything" | { grep e || true; }
### no error
$ echo $?
0
### DopeGhoti's "no-op" version
### (Potentially avoids spawning a process, if `true` is not a builtin):
$ echo "anything" | { grep e || :; }
### no error
$ echo $?
0

The "||" means "or". If the first part of the command "fails" (meaning "grep e" returns a non-zero exit code) then the part after the "||" is executed, succeeds and returns zero as the exit code (true always returns zero).

echo "anything" | { grep e || true; }

Explanation:

$ echo "anything" | grep e
### error
$ echo $?
1 

$ echo "anything" | { grep e || true; }
### no error
$ echo $?
0 

### DopeGhoti's "no-op" version
### (Potentially avoids spawning a process, if `true` is not a builtin):
$ echo "anything" | { grep e || :; }
### no error
$ echo $?
0

The || means "or". If the first part of the command "fails" (meaning grep e returns a non-zero exit code) then the part after the || is executed, succeeds and returns zero as the exit code (true always returns zero).

echo "anything" | grep e || true

Explanation:

$ echo "anything" | grep e
### error
$ echo $?
1
$ echo "anything" | grep e || true
### no error
$ echo $?
0
### DopeGhoti's "no-op" version
### (Potentially avoids spawning a process, if `true` is not a builtin):
$ echo "anything" | grep e || :
### no error
$ echo $?
0

The "||" means "or". If the first part of the command "fails" (meaning "grep e" returns a non-zero exit code) then the part after the "||" is executed, succeeds and returns zero as the exit code (true always returns zero).

echo "anything" | { grep e || true; }

Explanation:

$ echo "anything" | grep e
### error
$ echo $?
1
$ echo "anything" | { grep e || true; }
### no error
$ echo $?
0
### DopeGhoti's "no-op" version
### (Potentially avoids spawning a process, if `true` is not a builtin):
$ echo "anything" | { grep e || :; }
### no error
$ echo $?
0

The "||" means "or". If the first part of the command "fails" (meaning "grep e" returns a non-zero exit code) then the part after the "||" is executed, succeeds and returns zero as the exit code (true always returns zero).