file-test-operators

File Test Operators
code format="bash" -a file True if file exists. -b file True if file exists and is a block special file. -c file True if file exists and is a character special file. -d file True if file exists and is a directory. -e file True if file exists. -f file True if file exists and is a regular file. -g file True if file exists and is set-group-id. -h file True if file exists and is a symbolic link. -k file True if file exists and its ``sticky'' bit is set. -p file True if file exists and is a named pipe (FIFO). -r file True if file exists and is readable. -s file True if file exists and has a size greater than zero. -t fd         True if file descriptor fd is open and refers to a ter- minal. -u file True if file exists and its set-user-id bit is set. -w file True if file exists and is writable. -x file True if file exists and is executable. -O file True if file exists and is owned by the effective user id. -G file True if file exists and is owned by the effective group id. -L file True if file exists and is a symbolic link. -S file True if file exists and is a socket. -N file True if file exists and has been modified since it was last read. file1 -nt file2 True if file1 is newer (according to modification date) than file2, or if file1 exists and file2 does not. file1 -ot file2 True if file1 is older than file2, or if file2  exists and file1 does not. file1 -ef file2 True if file1 and file2 refer to the same  device  and inode numbers. -o optname True if shell option optname is enabled. See the list of options  under  the description of the -o option to          the set builtin below. -z string True if the length of string is zero. string -n string True if the length of string is non-zero.

string1 == string2 True if the strings are equal. = may be used in place of == for strict POSIX compliance.

string1 != string2 True if the strings are not equal.

string1 < string2 True if string1 sorts before string2 lexicographically in the current locale.

string1 > string2 True if string1 sorts after string2  lexicographically in the current locale.

arg1 OP arg2 OP is one of -eq, -ne, -lt, -le, -gt, or  -ge. These arithmetic binary  operators  return  true  if arg1 is          equal to, not equal to, less than, less than  or  equal to, greater  than,  or  greater than or equal to arg2, respectively. Arg1 and arg2 may be positive or  nega- tive integers.

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