diff命令在bash shell脚本中不起作用

Question

I am trying to run

diff <(tar -tvf HIVE_CLIENT.tar.gz | sort) <(tar -tvf YARN_CLIENT.tar.gz | sort) 

putting this command inside script, when I execute script it shows error

syntax error near unexpected token `(' "

But when I do not put inside script rather than run from shell directly it works.

Answer 1

Probably your script is run with /bin/sh and not with /bin/bash , but command substitution is a bash feature and not implemented in sh. So I suppose you are using bash as your shell which is why it is working from the command line.

Try adding this prefix to your script, and remove existing shebangs (like #!/bin/sh or similar):

#!/bin/bash

Answer 2

You should try following two actions:

1. Use #!/bin/bash as your shebang (First line of your script)

2. This may be needed based on your bash , use only if opetion 1 does not help. Use following commands to flip between posix mode which is needed for process substitution:

    set +o posix diff <(tar -tvf HIVE_CLIENT.tar.gz | sort) <(tar -tvf YARN_CLIENT.tar.gz | sort) set -o posix 

   Example:

    wc -l <(ls -lrt) sh: syntax error near unexpected token `(' set +o posix wc -l <(ls -lrt) 114 /dev/fd/00 set -o posix wc -l <(ls -lrt) sh: syntax error near unexpected token `('