Ggtcf

I want a unix command (that I will call in a ControlM job) that changes the value of the first column of my .csv file (not the header line), with the date of the previous day (expected format : YYYY-MM-DD).

I tried many commands but none of them do want I want :

tmp=$(mktemp) && awk -F| -v val=`date -d yesterday +%F` 'NR>1 gsub($1,val)' file.csv > "$tmp" && mv "$tmp" file.csv

or :

awk -F| -v val=`date -d yesterday +%F` 'gsub($1, val)1' file.csv

even tried gensub but not working.

Example of what I want :
Input :

VALUE_DATE;TRADE_DATE;DESCR1;DESCR2
2019-03-05;2017-11-15;BRIDGE;HELLO
2019-03-05;2018-03-17;WORK;DATA

Output I want (as today is 2019-03-07):

VALUE_DATE;TRADE_DATE;DESCR1;DESCR2
2019-03-06;2017-11-15;BRIDGE;HELLO
2019-03-06;2018-03-17;WORK;DATA

Can you help please and give me examples of commands that should work, I'm not finding a solution.

Thanks a lot

Could you please try following first?(not saving output into file.csv itself it will print output on terminal once happy then you could use answer
provided at last of this post)

awk -v val=$(date -d yesterday +%F) 'BEGINFS=OFS=";"FNR>1$1=val 1' file.csv

Problems identified in OP's code(and fixed in my suggestion):

1- Use of backtick is depreciated now to save shell variable's values, so instead use val=$(date....) for declaring awk's variable named val.

2- Use of -F, you have set your field separator as | which is pipe but when we see your provided sample Input_file carefully it is delimited with ;(semi colon) NOT | so that is also one of the reason why it is not reflecting in output.

3- Since use of gsub($1,val), replaces whole line to only with value of variable val
because
syntax of gsub is something like: gsub(your_regex/value_needs_to_be_replaced,"new_value"/variable_which_should_be_there_after_replacement,current_line/variable). Since you have defined wrong field separator so whole line being treated as $1 and thus when you print it by doing awk -F| -v val=$(date -d yesterday +%F) 'NR>1 gsub($1,val) 1' file.csv it will only print previous dates.

4- 4th and main issue is you have NOT printed anything, so even you did mistakes you will NOT see any output either on terminal or in output file.

If happy then you could run your own command to make changes into Input_file itself.(I am assuming that you are having propervaluein your tmp variable here)

tmp=$(mktemp) && awk -v val=$(date -d yesterday +%F) 'BEGINFS=OFS=";"FNR>1$1=val 1' file.csv > "$tmp" && mv "$tmp" file.csv