我想使用一些 sed 命令修改 csv 文件，但仅限于与某些正则表达式匹配的行。
我有一个在脚本中运行良好的 grep 命令：
#!/usr/bin/bash
egrep '^[A-Z][a-z]*,2018' happiness.csv
以及所需的正确工作的 sed 命令：
#!/usr/bin/bash
sed -re '
s/(^|,)(,|$)/\1NULL\2/g; s/(^|,)(,|$)/\1NULL\2/g
s/[a-z]/\U&/g
s/([0-9]+\.[0-9]{2})[0-9]+/\1/g
' happiness.csv
当我将它们组合在一个脚本中时，grep 命令被省略，脚本仅运行 sed 命令：
#!/usr/bin/bash
egrep '^[A-Z][a-z]*,2018' happiness.csv
sed -re '
s/(^|,)(,|$)/\1NULL\2/g; s/(^|,)(,|$)/\1NULL\2/g
s/[a-z]/\U&/g
s/([0-9]+\.[0-9]{2})[0-9]+/\1/g
' happiness.csv
样本数据：
Country name,Year,Life Ladder,Log GDP per capita,Social support,Healthy life expectancy at birth,Freedom to make life choices,Generosity,Perceptions of corruption,Positive affect,Negative affect,Confidence in national government,Democratic Quality,Delivery Quality,Standard deviation of ladder by country-year,Standard deviation/Mean of ladder by country-year,GINI index (World Bank estimate),"GINI index (World Bank estimate), average 2000-16","gini of household income reported in Gallup, by wp5-year","Most people can be trusted, Gallup","Most people can be trusted, WVS round 1981-1984","Most people can be trusted, WVS round 1989-1993","Most people can be trusted, WVS round 1994-1998","Most people can be trusted, WVS round 1999-2004","Most people can be trusted, WVS round 2005-2009","Most people can be trusted, WVS round 2010-2014"
Afghanistan,2008,3.723589897,7.168690205,0.450662315,50.79999924,0.718114316,0.177888572,0.88168633,0.517637193,0.25819549,0.61207211,-1.929689646,-1.655084372,1.774661899,0.476599723,,,,,,,,,,
Afghanistan,2009,4.401778221,7.333789825,0.55230844,51.20000076,0.678896368,0.200178429,0.850035429,0.583925605,0.23709242,0.611545205,-2.044092655,-1.635024786,1.722687602,0.391361743,,,0.441905767,0.286315262,,,,,,
Afghanistan,2018,4.75838089,7.386628628,0.539075196,51.59999847,0.60012722,0.13435255,0.706766069,0.61826545,0.275323808,0.299357414,-1.991810083,-1.617176056,1.878621817,0.394802749,,,0.327318162,0.275832713,,,,,,
Afghanistan,2011,3.83171916,7.415018559,0.521103561,51.91999817,0.495901406,0.172136664,0.731108546,0.611387312,0.267174691,0.307385713,-1.919018269,-1.616221189,1.78535974,0.465942234,,,0.336764246,,,,,,,
Afghanistan,2012,3.782937527,7.517126083,0.520636737,52.24000168,0.530935049,0.244272724,0.775619805,0.710384727,0.267919123,0.435440153,-1.842995763,-1.40407753,1.798283219,0.47536689,,,0.344539613,,,,,,,
Afghanistan,2013,3.572100401,7.522237778,0.48355186,52.56000137,0.577955365,0.070402659,0.8232041,0.620584846,0.273328096,0.482847273,-1.879708767,-1.403035522,1.223689914,0.342568725,,,0.304368466,,,,,,,
Afghanistan,2014,3.130895615,7.516955376,0.525568426,52.88000107,0.508514047,0.113184482,0.871241987,0.531691492,0.374860734,0.409047514,-1.773256779,-1.312502503,1.395396113,0.445685923,,,0.413973927,,,,,,,
Afghanistan,2015,3.982854605,7.500538826,0.528597236,53.20000076,0.388927579,0.089090675,0.880638301,0.553553164,0.339276046,0.260557145,-1.84436357,-1.29159379,2.16061759,0.542479634,,,0.59691757,,,,,,,
Albania,2018,4.220168591,7.497038364,0.559071779,53,0.522566199,0.051364917,0.793245554,0.564952672,0.348332286,0.324989557,-1.855426311,-1.392712831,1.796219468,0.42562741,,,0.418629497,,,,,,,
期望的输出：
COUNTRY NAME,YEAR,LIFE LADDER,LOG GDP PER CAPITA,SOCIAL SUPPORT,HEALTHY LIFE EXPECTANCY AT BIRTH,FREEDOM TO MAKE LIFE CHOICES,GENEROSITY,PERCEPTIONS OF CORRUPTION,POSITIVE AFFECT,NEGATIVE AFFECT,CONFIDENCE IN NATIONAL GOVERNMENT,DEMOCRATIC QUALITY,DELIVERY QUALITY,STANDARD DEVIATION OF LADDER BY COUNTRY-YEAR,STANDARD DEVIATION/MEAN OF LADDER BY COUNTRY-YEAR,GINI INDEX (WORLD BANK ESTIMATE),"GINI INDEX (WORLD BANK ESTIMATE), AVERAGE 2000-16","GINI OF HOUSEHOLD INCOME REPORTED IN GALLUP, BY WP5-YEAR","MOST PEOPLE CAN BE TRUSTED, GALLUP","MOST PEOPLE CAN BE TRUSTED, WVS ROUND 1981-1984","MOST PEOPLE CAN BE TRUSTED, WVS ROUND 1989-1993","MOST PEOPLE CAN BE TRUSTED, WVS ROUND 1994-1998","MOST PEOPLE CAN BE TRUSTED, WVS ROUND 1999-2004","MOST PEOPLE CAN BE TRUSTED, WVS ROUND 2005-2009","MOST PEOPLE CAN BE TRUSTED, WVS ROUND 2010-2014"
AFGHANISTAN,2018,2.69,7.49,-0.50,52.59,0.37,-0.08,0.92,0.42,0.40,0.36,NULL,NULL,1.40,0.52,NULL,NULL,0.29,NULL,NULL,NULL,NULL,NULL,NULL,
ALBANIA,2018,4.63,9.07,-0.82,65.80,0.52,-0.01,0.87,0.55,0.24,0.30,-0.04,-0.42,1.76,0.38,NULL,0.30,NULL,NULL,NULL,NULL,0.24,0.23,NULL, ARGENTINA,2018,5.48,9.16,-0.83,66.19,0.52,-0.16,0.86,0.64,0.27,NULL,0.04,-0.26,1.91,0.34,NULL,0.30,0.61,0.11,NULL,NULL,0.24,0.23,NULL,
您可以使用相同的正则表达式进行搜索egrep，并确保对所有替换命令进行分组：
sed -nE '1p; /^[A-Z][a-z]*,2018/ {
s/(^|,)(,|$)/\1NULL\2/g; s/(^|,)(,|$)/\1NULL\2/g
s/[a-z]+/\U&/g
s/([0-9]+\.[0-9]{2})[0-9]+/\1/gp
}' happiness.csv
AFGHANISTAN,2018,4.75,7.38,0.53,51.59,0.60,0.13,0.70,0.61,0.27,0.29,-1.99,-1.61,1.87,0.39,NULL,NULL,0.32,0.27,NULL,NULL,NULL,NULL,NULL,NULL
ALBANIA,2018,4.22,7.49,0.55,53,0.52,0.05,0.79,0.56,0.34,0.32,-1.85,-1.39,1.79,0.42,NULL,NULL,0.41,NULL,NULL,NULL,NULL,NULL,NULL,NULL