Adding-C ~ / stuff to the tar command achieves the same effect ; the example just shows that subshells can consume input too .

u4e3ataru547du4ee4 u6dfbu52a0 -C~/stuffu53efu4ee5 u8d77 u5230 u4e0eu524du9762u76f8u540cu7684u4f5cu7528uff1bu8fd9u4e2au793au4f8bu663eu793au4e86 subshellu4e5fu53efu4ee5u4f7fu7528u8f93u5165u3002

The use of the brackets ensures the commands are grouped and executed in a subshell .

u4f7fu7528u62ecu53f7u662fu4fddu8bc1u6b64u547du4ee4u5206u5728u4e00u4e2au7ec4u4e2duff0cu5e76u4e14u5728u5b50 shellu4e2du6267u884cu3002

The paper calculates the ionization potentails and the subshell energies of ions by the improved screened hydrogenic ionization model .

u7528u6539u8fdbu7684u5c4fu853du6c22u79bbu5b50u6a21u578b1w_1639u8ba1u7b97u4e86u79bbu5b50u7684u7535u79bbu52bfu548cu6b21 u58f3u5c42u80fdu91cfu3002

Here the subshell command du-sh work | cut-f1 yields the total size of the work directory in a format compatible with pv .

u5728u8fd9u91ccuff0c u5b50 shellu547du4ee4du-shworkcut-f1u4ee5u4e0epvu517cu5bb9u7684u683cu5f0fu751fu6210u5de5u4f5cu76eeu5f55u7684u603bu5927u5c0fu3002

The command in parentheses is a subshell : Commands in the subshell don 't affect the environment of the current shell .

u62ecu53f7u4e2du7684u547du4ee4u4e3au4e00u4e2a subshelluff1asubshellu4e2du7684u547du4ee4u4e0du4f1au5f71u54cdu5f53u524dshellu7684u73afu5883u3002

You can generally do this by running a list of commands in a subshell or by running a list of commands in the current shell .

u60a8u4e00u822cu53efu4ee5u901au8fc7u5728u67d0u4e2a Subshellu4e2du8fd0u884cu4e00u4e2au547du4ee4u5217u8868u6216u901au8fc7u5728u5f53u524dShellu4e2du8fd0u884cu4e00u4e2au547du4ee4u5217u8868u6765u5b9eu73b0u6b64 u76eeu7684u3002

According to Hund 's rules we present a concise formula with which atomic or ionic ground state can be difined only by the electronic number of not filled subshell .

u6839u636eHundu5b9au5219uff0cu7ed9u51fau4e86u76f4u63a5u7528u672au6ee1 u58f3u5c42u7535u5b50u6570u786eu5b9au539fu5b50u3001u79bbu5b50u57fau6001u7684u6570u5b66u516cu5f0fu3002

The parentheses effectively execute the statements in a subshell .

u5706u62ecu53f7 u8ba9u8bedu53e5u5728u4e00 u4e2au5b50 shellu4e2du6267u884cu3002

The series of commands collected in parentheses runs in a subshell and does not affect the state of the current shell .

u5728u5706u62ecu53f7u4e2du7684u7cfbu5217u547du4ee4u5c06u5728u4e00 u4e2au5b50 Shellu4e2du8fd0u884cuff0cu5e76u4e14u4e0du4f1au5bf9u5f53u524dShellu7684u72b6u6001u4ea7u751fu5f71u54cdu3002

Nevertheless some drift is likely to occur because it does take a finite amount of time to launch each subshell for the background processing .

u4f46u662fuff0cu8fd9u4e2au8fc7u7a0bu4f1au53d1u751fu4e00u4e9bu65f6u95f4u504fu5deeuff0cu56e0u4e3au9700u8981u82b1u8d39u4e00u4e9bu65f6u95f4u542fu52a8u6bcfu4e2a u5b50 shell u811au672cu6765u8fdbu884cu540eu53f0u5904u7406u3002

While it 's common to run a subshell to pipe aggregated output to a single command you can also use a subshell to expand a command in place just like back ticks .

u5c3du7ba1u901au5e38u8fd0u884cu5b50 Shell u5c06u805au5408u7684u8f93u51fau901au8fc7u7ba1u9053 u4f20u9012u7ed9u5355u4e2au547du4ee4uff0cu4f46u60a8u8fd8u53efu4ee5u4f7fu7528u5b50Shellu5bf9u547du4ee4u8fdbu884cu6269u5c55uff0cu5c31u50cfu53cdu52feu53f7u90a3u6837u3002

Hence a full subshell has zero angular momentum and is spherically symmetric .

u4e8eu662fuff0cu4e00u4e2au5df2u7ecf u586bu6ee1 u7684 u652f u58f3u5c42u7684u89d2u52a8u91cfu4e3au96f6uff0cu5e76u4e14u662fu7403u9762u5bf9u79f0u7684u3002

Because the subshell has so many uses you might prefer to use it always instead of a combination or the back tick operators .

u56e0u4e3a u5b50 Shellu6709u8bb8u591au7528u9014uff0cu6240u4ee5u4e0eu7ec4u5408u6216u8005u53cdu52feu53f7u64cdu4f5cu7b26u76f8u6bd4uff0cu60a8u53efu80fdu66f4u559cu6b22u4f7fu7528u5b83u3002

Changes made in the subshell for example changing directory do not affect your command line but it does affect the environment of the subshell .

subshellu4e2du8fdbu884cu7684u66f4u6539uff0cu4f8bu5982u66f4u6539u76eeu5f55uff0cu4e0du4f1au5f71u54cdu5230u60a8u7684u547du4ee4u884cuff0cu4f46u662fu5b83u5c06u5f71u54cdsubshellu7684u6267u884cu73afu5883u3002

Finally the back quotes both interpret the variable and run the intermediate result as a subshell .

u6700u540euff0cu53cdu6487u53f7u89e3u91cau53d8u91cfu5e76u4f5cu4e3au5b50 shellu8fd0u884cu4e2du95f4u7ed3u679cu3002

Determination of the atomic states of an electron configuration for the same subshell in the j (?) - coupling scheme

u786eu5b9au540c u79d1u7535u5b50u539fu5b50u6001u7684 Jju8026 u5408u6cd5

Better yet a subshell can contain another subshell so expansions can be nested too .

u7136u800cu66f4u6709 u4ef7u503cu7684u662fuff0c u5b50 Shellu53efu4ee5u5305u542bu53e6u4e00u4e2au5b50Shelluff0cu6240u4ee5u8fd8u53efu4ee5u8fdbu884cu5d4cu5957u6269u5c55u3002

By setting errexit the subshell immediately terminates when the first command stops .

u901au8fc7u8bbeu7f6e errexituff0c u5b50 u5916u58f3 u5c06u76f4u63a5u5728u7b2cu4e00u4e2au547du4ee4u505cu6b62u65f6u7ec8u6b62u3002

Using the subshell you can collectively redirect their standard and error output for the entire block instead of for each individual command .

u901au8fc7u4f7fu7528 u5b50 u5916u58f3uff0cu53efu4ee5u5bf9u6574u4e2au5757uff08u800cu4e0du662fu5355u4e2au547du4ee4uff09u7684u6807u51c6u548cu9519u8befu8f93u51fau8fdbu884cu96c6u4f53u91cdu5b9au5411u3002

Especially for atomic subshell and shell structure of transition elements are correctly predicated .

u8be5 u7406u8bba u53efu4ee5 u63edu793au539fu5b50u7684 u5168u90e8u58f3u5c42u7ed3u6784uff0c u4ea7u751f u57fau672cu5408u7406u7684 u7535u5b50 u6570uff0cu5c24u5176u662fu6b63u786eu7684u9884u793au4e86u539fu5b50u7684 u4e9a u58f3u5c42u7ed3u6784u548cu8fc7u6e21u5143u7d20u7684u58f3u5c42u7ed3u6784uff1b