I have a text file which contains several occurrences of dates. All the dates are written in the format Mon-DD-YYYY. I have to update all these dates in the current date keeping the format Mon-DD-YYYY.
The scripting language is bash. One big problem is that I have no idea how to match a specific format date with sed, awk, bash built-in functions, etc.
Could you help me, please?
Set current_date=$(date +"%m-%d-%Y") or to whatever date you want and then run
sed -i.bak "s/[0-9]\{2\}-[0-9]\{2\}-[0-9]\{4\}/$current_date/g" your_file.txt With this, you can match any date in a file and replace it with current_date
The sed command in this case works like: sed "s/tobereplace/replacement/g". The g at the end stands for global, that means every occurrence of the tobereplace pattern will be replaced by replacement.
For tobereplaced the regex pattern [0-9]\{2\}-[0-9]\{2\}-[0-9]\{4\} is used, which translates to
[0-9] any number from 0 to 9\{2\} two times\{4\}Edit: As FelixJN mentioned in the comment, you probably wanted the month as a string, for that you would use %b in the date command and replace the first part of the regex like this:
current_date=$(date "+%b-%d-%Y") sed -Ei "s/[A-Z][a-z]\{2\}-[0-9]\{2\}-[0-9]\{4\}/$current_date/g" your_file.txt In this case, the regex works like this:
[A-Z] Matches any uppercase letter from A to Z.[a-z]\{2\} Matches any lowercase letter from a to z two timesThe rest is the same as mentioned above
Mon in OP's request asks for using %b and [A-Z][a-z]\{2\} for the month. Mon-DD-YYYY I mean, for instance, Jan-14-2023 /(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)-[0-9]{2}-[0-9]{4}/ -- use sed -E to not have to escape the regex characters Using Raku (formerly known as Perl_6)
If you're starting from a numeric (2-digit) month:
~$ raku -pe 's:g/ \d**2 \- \d**2 \- \d**4 /{Date.today.mm-dd-yyyy("-")}/;' file If you're starting from an alphabetic (3-letter) month:
~$ raku -pe 'BEGIN my %h = [Z=>] 1..12, <Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec>; \ s:g/ <{%h.values}> \- \d**2 \- \d**4 /{ join "-", %h{Date.today.month}, Date.today.day, Date.today.year }/;' file Sample Input:
Delaware Dec-07-1787; Pennsylvania Dec-12-1787; New Jersey Dec-18-1787; Georgia Jan-02-1788; Connecticut Jan-09-1788; Massachusetts Feb-06-1788; Maryland Apr-28-1788; South Carolina May-23-1788; New Hampshire Jun-21-1788; Virginia Jun-25-1788; New York Jul-26-1788; North Carolina Nov-21-1789; Rhode Island May-29-1790; Vermont Mar-04-1791; Kentucky Jun-01-1792; Tennessee Jun-01-1796; Ohio Mar-01-1803; Louisiana Apr-30-1812; Indiana Dec-11-1816; Mississippi Dec-10-1817; Illinois Dec-03-1818; Alabama Dec-14-1819; Maine Mar-15-1820; Missouri Aug-10-1821; Arkansas Jun-15-1836; Michigan Jan-26-1837; Florida Mar-03-1845; Texas Dec-29-1845; Iowa Dec-28-1846; Wisconsin May-29-1848; California Sep-09-1850; Minnesota May-11-1858; Oregon Feb-14-1859; Kansas Jan-29-1861; West Virginia Jun-20-1863; Nevada Oct-31-1864; Nebraska Mar-01-1867; Colorado Aug-01-1876; North Dakota Nov-02-1889; South Dakota Nov-02-1889; Montana Nov-08-1889; Washington Nov-11-1889; Idaho Jul-03-1890; Wyoming Jul-10-1890; Utah Jan-04-1896; Oklahoma Nov-16-1907; New Mexico Jan-06-1912; Arizona Feb-14-1912; Alaska Jan-03-1959; Hawaii Aug-21-1959; Sample Output:
Delaware Jul-4-2023; Pennsylvania Jul-4-2023; New Jersey Jul-4-2023; Georgia Jul-4-2023; Connecticut Jul-4-2023; Massachusetts Jul-4-2023; Maryland Jul-4-2023; South Carolina Jul-4-2023; New Hampshire Jul-4-2023; Virginia Jul-4-2023; New York Jul-4-2023; North Carolina Jul-4-2023; Rhode Island Jul-4-2023; Vermont Jul-4-2023; Kentucky Jul-4-2023; Tennessee Jul-4-2023; Ohio Jul-4-2023; Louisiana Jul-4-2023; Indiana Jul-4-2023; Mississippi Jul-4-2023; Illinois Jul-4-2023; Alabama Jul-4-2023; Maine Jul-4-2023; Missouri Jul-4-2023; Arkansas Jul-4-2023; Michigan Jul-4-2023; Florida Jul-4-2023; Texas Jul-4-2023; Iowa Jul-4-2023; Wisconsin Jul-4-2023; California Jul-4-2023; Minnesota Jul-4-2023; Oregon Jul-4-2023; Kansas Jul-4-2023; West Virginia Jul-4-2023; Nevada Jul-4-2023; Nebraska Jul-4-2023; Colorado Jul-4-2023; North Dakota Jul-4-2023; South Dakota Jul-4-2023; Montana Jul-4-2023; Washington Jul-4-2023; Idaho Jul-4-2023; Wyoming Jul-4-2023; Utah Jul-4-2023; Oklahoma Jul-4-2023; New Mexico Jul-4-2023; Arizona Jul-4-2023; Alaska Jul-4-2023; Hawaii Jul-4-2023; The replacement half uses raku code in a {...} curly-brace wrapped codeblock to generate the replacement date. Note: in the recognition domain, the above code (second answer) uses <{%h.values}> to generate months. You could use <alpha>**3 instead, or even @GlennJackman's list of months (in the comments).
Shipley, Samuel. "list of U.S. states’ dates of admission to the union". Encyclopedia Britannica, 11 Feb. 2020, https://www.britannica.com/topic/list-of-U-S-states-by-date-of-admission-to-the-Union-2130026. Accessed 4 July 2023.
https://docs.raku.org/type/Date
https://docs.raku.org/routine/mm-dd-yyyy
https://raku.org
